吉田 泰志

© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Chiral α-amino-δ-keto esters are important precursors of organocatalysts, pharmaceuticals, and biochemically interesting molecules. The organocatalytic asymmetric umpolung reaction of imines has been developed to obtain chiral amines in a highly enantioselective manner. Herein, we report the organocatalytic asymmetric umpolung synthesis of α-amino-δ-keto esters in high yield (up to 95% ee, >20/1 r.r.). (Figure presented.).

© 2018 by Japan Oil Chemists’ Society. We designed and synthesized a series of N,N-disubstituted allylic amine type aminophosphines 2, 3 and 4, which are derivatives of chiral ligands 1. Aminophosphines 2–4 (except 2a) exist in C(aryl)– N(amine) bond axial chirality by chiral HPLC analysis. Both enantiomeric isomers of 4b were successfully obtained in an enantiomerically pure form. We demonstrated that 1a, 1b, and 4b can be used as effective chiral ligands for the palladium-catalyzed asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate with malonates in high enantioselectivities (up to 90% ee).

© 2018 American Chemical Society. Asymmetric Diels-Alder reaction was achieved under achiral conditions. Reaction of prochiral 2-methylfuran and N-phenylmaleimide in heptane or hexane solution at 80 °C efficiently gave a conglomerate crystal of exo-type Diels-Alder adduct selectively, and continuous suspension of the reaction mixture with glass beads promoted attrition-enhanced deracemization, leading to an optically active exo-adduct in 90% ee.

© 2018 the Partner Organisations. Regrettably, in the original article on page 981 the wrong name was provided for compound 4b. The correct name of compound 4b is 1-cinnamyl-2-phenylnaphtho[2,1-b]furan. Moreover, some of the structures described in Table 2 are incorrect. The correct structures are shown below. (Table Presented).

© 2018 The Royal Society of Chemistry. The authors regret that there was an error in the structures of 1f, 3fa and 4f. In Table 2, entry 6, the correct structures for 1f, 3fa and 4f should have R2 = 3,4-(CHvCH)2. In addition, incorrect names were given for compounds 3fa and 4f in the Experimental section. The correct name for compound 3fa is 1-cinnamyl-2-phenylnaphtho[2,1-b]furan and for compound 4f is 2-phenylnaphtho[2,1-b]furan. The original ESI was replaced by a correspondingly revised version on 5th July 2018. Furthermore, reference 14 was wrong. The correct reference is shown below. 14. L. Liu, X. Ji, J. Dong, Y. Zhou and S.-F. Yin, Org. Lett., 2016, 18, 3138. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.

A series of fluorescent dimeric imidazo[1,5-a]pyridinium salts have been synthesized. These salts displayed large Stokes shifts (up to 196 nm), possessed good water solubility, and exhibited blue to yellow emission (Phi(em) = up to 0.50) in solution. When one specific compound was used for co-incubation of HeLa cells, green fluorescent signals were observed. The combined use of the salt and commercially available blue fluorescent dye realized the double staining of HeLa cells under the single UV excitation.

Asymmetric Diels-Alder reaction was achieved under achiral conditions. Reaction of prochiral 2-methylfuran and N-phenylmaleimide in heptane or hexane solution at 80 degrees C efficiently gave a conglomerate crystal of exo-type Diels-Alder adduct selectively, and continuous suspension of the reaction mixture with glass beads promoted attrition-enhanced deracemization, leading to an optically active exo-adduct in 90% ee.

Regrettably, in the original article on page 981 the wrong name was provided for compound 4b. The correct name of compound 4b is 1-cinnamyl-2-phenylnaphtho[2,1-b]furan. Moreover, some of the structures described in Table 2 are incorrect. The correct structures are shown below. (Table Presented).

Two boron complexes of 1-(o-hydroxyphenyl)imidazo[1,5-a]pyridine, which were named as BOHPIP, have been synthesized. These complexes exhibited blue emission in solution with high quantum yields (Phi FL = up to 0.71). In addition, 1-(o-hydroxyphenyl)imidazo[1,5-a]pyridine-BPh2 complex showed the strong blue emission even in the solid state (Phi FL = 0.58). (C) 2018 Elsevier Ltd. All rights reserved.

We previously reported the synthesis of BICMAP (1a) via 6-diphenylphosphino-2,3-dihydrobenzofuran as a key intermediate. However, we did not successfully synthesize BICMAP analogues via a similar synthetic route. Herein we report the second-generation synthesis of BICMAP and its derivatives via diethylphosphonate as a key intermediate. (C) 2018 Elsevier Ltd. All rights reserved.

Photodimerization of 3-arylindenones in solution and in the solid state was examined. Irradiation of 3-arylindenones in benzene exclusively gave C2-symmetric anti-HH cyclobutane dimers in good yields. In contrast, photolysis in the solid state afforded syn-HH cyclobutane dimers efficiently, which was considerably influenced by the molecular arrangement in the crystal lattice.

Photodimerization of 3-arylindenones in solution and in the solid state was examined. Irradiation of 3-arylindenones in benzene exclusively gave C-2-symmetric antiHH cyclobutane dimers in good yields. In contrast, photolysis in the solid state afforded syn-HH cyclobutane dimers efficiently, which was considerably influenced by the molecular arrangement in the crystal lattice.

We found that the hydrazone-Pd-catalyzed direct intermolecular reaction of o-alkynylphenols with allylic acetates afforded the corresponding 2-substituted-3-allylbenzofuran derivatives. This reaction proceeded smoothly at room temperature using a hydrazone-Pd catalyst system.

C-2-Symmetric cyclic polyethers were conveniently provided by the photochemical dimerization of covalently-linked 2-chromonecarboxylic esters. Irradiation of polyethers possessing 2-chromonecarboxylate groups at both ends efficiently promoted intramolecular [2+2] cyclobutane formation leading to 14- to 23-membered cyclic polyethers in good chemical yields and quantum efficiencies. X-ray crystallographic analysis revealed that the stereochemistry of the cyclobutane was the C-2-symmetric structure.

Asymmetric synthesis involving photochemical dimerization<br /> of a prochiral flavonoid derivative in solution without<br /> any chiral source was achieved. Irradiation of ethyl 6-<br /> bromochromonecarboxylate in solution efficiently gave a C2-<br /> chiral anti-head-to-head dimer in excellent chemical yield with<br /> good quantum efficiency (Φ365 = 0.15). X-ray crystallographic<br /> analysis revealed that the dimer crystallized as a conglomerate<br /> of C2 space group. The crystalline dimer precipitated upon irradiation of the monomer in solution, and indirect racemization<br /> of the dimer through a reversible photoreaction in solution and<br /> selective crystallization simultaneously occurred to give the C2-<br /> chiral dimer in optically active form with up to 80 % ee. Optically<br /> active photoproducts could be obtained by simply irradiating<br /> achiral materials in solution without an external chiral<br /> source.

We designed and synthesized dimeric imidazo[1, 5-a]pyridines possessing various aryl groups at 1,1'-positions. The solution of these derivatives exhibited fluorescence emission in wavelength range of 487-512 nm. The fluorescence emissions were slightly red-shifted under acidic condition by addition of trifluoroacetic acid. Furthermore, the original fluorescence spectra were observed after the addition of triethylamine as a base.

&lt;I&gt;C&lt;/I&gt;&lt;SUB&gt;2&lt;/SUB&gt;-Symmetric cyclic polyethers were conveniently provided<br /> by the photochemical dimerization of covalently-linked 2-<br /> chromonecarboxylic esters. Irradiation of polyethers possessing<br /> 2-chromonecarboxylate groups at both ends efficiently promoted<br /> intramolecular [2+2] cyclobutane formation leading to 14- to<br /> 23-membered cyclic polyethers in good chemical yields and<br /> quantum efficiencies. X-ray crystallographic analysis revealed<br /> that the stereochemistry of the cyclobutane was the &lt;I&gt;C&lt;/I&gt;&lt;SUB&gt;2&lt;/SUB&gt;-<br /> symmetric structure.

© 2017 Wiley-VCH Verlag GmbH &amp; Co. KGaA, Weinheim We have demonstrated the Mizoroki–Heck reaction of aryl iodides with aryl allyl ethers using 1.5 mol% of imidazo[1, 5-a]pyridine–Pd catalytic system. Aryl cinnamyl ethers were obtained in moderate-to-high yield under mild reaction conditions.

© 2017 Wiley-VCH Verlag GmbH &amp; Co. KGaA, Weinheim The catalytic asymmetric umpolung reaction of ketimines is of great importance, because it can easily provide chiral amines bearing a tetrasubstituted carbon atom on its asymmetric center. Because amino acids with a tetrasubstituted carbon center are useful due to their wide applicability as pharmaceuticals and chiral building blocks, their enantioselective synthesis has great significance in organic synthesis. Herein, we demonstrate a metal-free novel phase-transfer-catalyzed highly regio- and enantioselective umpolung Michael reaction of α-imino esters, which provides amino acid derivatives in high yields with up to 98 % ee. The products are successfully converted into chiral amino acid derivative and δ-lactone with high enantiopurity.

© 2017 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim We have found that Suzuki–Miyaura-type reactions of dibromoalkenes with arylboronic acids using a hydrazone–Cu catalyst system proceeded smoothly under mild conditions to afford the corresponding internal alkyne derivatives in good yields. Furthermore, we also succeeded in the synthesis of o-allyloxy(ethynyl)benzene derivatives, which are known to be effective precursors of various heterocyclic compounds, through this reaction.

© 2017 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim We have found that Suzuki–Miyaura-type reactions of o-allyloxy(bromoethynyl)benzenes with arylboronic acids using a hydrazone/Cu catalyst system proceeded smoothly in iPrOH under mild conditions to afford the corresponding o-allyloxy(arylethynyl)benzene derivatives in good yields without decomposition of the allyloxy group. We have further demonstrated that annulation and enyne metathesis of the o-allyloxy(arylethynyl)benzene derivatives using transition-metal catalysts led to various heterocyclic compounds.

Irradiation of prochiral (&lt;I&gt;E&lt;/I&gt;)-aroylacrylamide with<br /> sunlight gave single-handed pyrrolinone quantitatively and<br /> with an enantiomeric excess (&lt;I&gt;ee&lt;/I&gt;) of over 99% under absolutely<br /> achiral conditions. The phenomenon was explained by<br /> photoisomerization and reversible cyclization followed by<br /> dynamic crystallization involving deracemization.

Single-handed -amino acid derivatives were generated from achiral precursors without an external chiral source. Conjugate addition of phenethylamine to an achiral aroyl acrylamide under homogeneous conditions gave the -amino amides in quantitative yields, which crystallized as a conglomerate of a P2(1) crystal system. Dynamic preferential crystallization or attrition-enhanced deracemization resulted in the formation of enantiomorphic crystals of 99% ee.

Unprecedented absolute asymmetric synthesis was carried out using frozen chirality derived from chiral crystals of achiral coumarin-3-carboxamide and carbenoids. An enantioselective cycloaddition reaction with a sulfur ylide gave an optically active cyclopropane up to 97% ee. Furthermore, a cycloaddition reaction with dichlorocarbene gave dihydrofuran in 93% ee. Nucleophilic addition of ylide or carbene occurs from the side of the carbonyl oxygen atom to avoid steric hindrance of substituents on the nitrogen atom.

Amino acid-derived novel chiral hypervalent iodine(V) reagents were synthesized from the corresponding chiral iodoarenes through DMDO oxidations. Their oxidation states were determined by the C-13 NMR chemical shifts of the ipso-carbon of the iodine atom, HRMS analysis, and elemental analyses. They were applied to the enantioselective hydroxylative dearomatization/[4+2]-dimerization cascade reactions of phenol derivatives to afford the desired products with up to 58% ee. (C) 2016 Elsevier Ltd. All rights reserved.

The annulation of 1-cinnamyloxy-2-ethynylbenzene derivatives using a hydrazone-palladium catalyst system proceeded smoothly and gave the corresponding 2-substituted-3-cinnamylbenzofurans in good-to-excellent yields.

Such chiral phosphine-internal olefin hybrid type ligands as N-1-adamantyl-N-cinnamylaniline derivatives 1 with C(aryl)-N(amine) bond axial chirality were synthesized and utilized for the palladium-catalyzed asymmetric allylic alkylation of indoles to afford the desired products in high enantioselectivities (up to 98% ee).

The annulation of 1-cinnamyloxy-2-ethynylbenzene derivatives using a hydrazone-palladium catalyst system proceeded smoothly and gave the corresponding 2-substituted-3-cinnamylbenzofurans in good-to-excellent yields.

© 2015 WILEY-VCH Verlag GmbH &amp; Co. KGaA, Weinheim. An enantio-, diastereo-, regio-, and chemoselective phosphine-catalyzed β,γ-umpolung domino reaction of allenic esters with dienones has been developed for the first time. The designed sequence, involving oxy-Michael and Rauhut-Currier reactions, produced highly functionalized tetrahydrobenzofuranones, bearing a chiral tetrasubstituted stereogenic center, in up to 96 % ee. Domino effect: An enantio-, diastereo-, regio-, and chemoselective phosphine-catalyzed β,γ-umpolung domino reaction of allenic esters with dienones has been developed for the first time. The designed sequence involving oxy-Michael and Rauhut-Currier reactions produced highly functionalized tetrahydrobenzofuranones bearing a chiral tetrasubstituted stereogenic center in up to 96 % ee.

The enantioselective oxidative coupling of 2-naphthols in water was established using dinuclear vanadium(V/IV) catalysis with 02 as the sole co-oxidant. In the vanadium-catalyzed reaction, the corresponding coupling products were obtained in good to excellent yields with up to 94% enantiomeric excess. In water, racemization of the coupling product was suppressed even at high temperature (70 degrees C). (C) 2015 Elsevier Ltd. All rights reserved.

A highly enantioselective aza-Morita-Baylis-Hillman (aza-MBH) reaction of isatin-derived ketimines with acrolein was established using beta-isocupreidine (beta-ICD) or alpha-isocupreine (alpha-ICPN) as a chiral acid-base organocatalyst. The present protocol readily furnished (S) or (R)-aza-MBH adducts with a chiral tetra-substituted carbon stereogenic center in up to 98% ee.

Enantioselective organocatalytic synthesis of tetrahydropyridines bearing a chiral tetrasubstituted carbon stereogenic center has been achieved. The spiro-type monoaryl phosphine catalyst, (R)-SITCP, was found to promote the formal [4+2] cycloaddition of saccharin-derived ketimines and -methyl allenoate to afford the corresponding six-membered N-heterocycles in high yields and excellent regioselectivities with up to 93% ee.

Enantioselective oxidative-coupling of polycyclic phenols, such as 2-anthracenol, 9- or 3-phenanthrol, and 5-chrysenol was established by using vanadium(V/IV) catalysis under air or 02 as a co-oxidant. In the vanadium catalyzed reaction, the corresponding coupling products were obtained in good to excellent yields with up to 93% enantiomeric excess. (C) 2014 Elsevier Ltd. All rights reserved.

The introduction of a 1,3-propanediamine unit at the 3-position of (S)-BINOL using a methylene spacer led to the formation of a chiral bifunctional organocatalyst for the aza-Morita-Baylis-Hillman (aza-MBH) reaction. The organocatalyst 1k mediated aza-MBH transformations with high chemical yields and with up to 82% ee. (C) 2013 Elsevier Ltd. All rights reserved.

An enantioselective organocatalyzed aza-MBH-type reaction of ketimines and allenoates has been developed. The present formal [2 + 2] cycloaddition produces highly functionalized azetidines with a chiral tetrasubstituted carbon stereogenic center in good to excellent yields and high enantioselectivities.

Vanadium-mediated enantioselective Friedel-Crafts (FC)-type reactions were established using the dinuclear vanadium complex (R-a,S,S)-1a. The vanadium complex promoted the FC-type reaction of imines with 2-naphthols or indoles to give corresponding adducts with high enantioselectivities.

The P-chirogenic organocatalysts were found to promote the enantioselective aza-Morita-Baylis-Hillman reaction of ketimines derived from acyclic alpha-keto esters. In the P-chirogenic organocatalyzed aza-MBH reactions, alpha,alpha-disubstituted alpha-amino acid derivatives were obtained in high yields with high enantioselectivities (up to 97% ee).

Room temperature chiral spiro ionic liquids 1 and 2 based on 1,2,3-triazolium salts, were synthesized via an intramolecular double Huisgen reaction. The preparation of the enantiomerically pure Spiro triazolium salts was achieved by resolution by HPLC using a chiral stationary phase column and subsequent N-dial-kylations of spiro triazoles 6 and 10. (c) 2012 Elsevier Ltd. All rights reserved.

Unique chiral spiro ionic liquids based on 1,2,3-triazolium salts were synthesized via an intramolecular double Huisgen reaction. The optical resolution of the liquid precursors and subsequent dialkylations leads to chiral spiro triazolium salts on a gram scale. (C) 2011 Elsevier Ltd. All rights reserved.

It&#039;s the hype: The asymmetric synthesis of 3-alkyl-4-oxyisochroman-1-one is achieved by oxylactonization of ortho-alk-1-enylbenzoate with a series of optically active hypervalent iodine(III) reagents prepared from lactate or valine as a chiral source (see scheme). The oxylactonization is highly regio-, diastereo-, and enantioselective. © 2010 Wiley-VCH Verlag GmbH &amp; Co. KGaA. © 2010 Wiley-VCH Verlag GmbH &amp; Co. KGaA.