Yoji Oderaotoshi

Enantioselective Michael addition reactions of malononitrile catalyzed by chiral Lewis acid and achiral amine catalysts

Abstract Reactions of malononitrile with 3-(2-alkenoyl)-2-oxazolidinones or 1-(2-alkenoyl)-4-bromo-3,5-dimethylpyrazoles can be doubly activated by the use of catalytic amounts (10 mol% each) of both ( R , R )-DBFOX/Ph·Ni(ClO 4 ) 2 ·3H 2 O and amines, to give the Michael adducts in high chemical yields with satisfactory enantioselectivities.

Direct asymmetric synthesis of oxazolines from olefins using a chiral nitridomanganese complex: a novel three-component coupling leading to chiral oxazolines

Abstract A new synthetic method for chiral oxazolines has been developed by N1 unit transfer to olefins using a chiral nitridomanganese complex. When trans -disubstituted styrenes were treated with chiral complex 1 in the presence of an acid chloride, oxazolines were obtained with high enantioselectivities (up to 92% ee). Furthermore, the produced oxazolines could be easily converted into β-amino alcohols, which are ephedrine derivatives.

Generation and cycloaddition of polymer-supported azomethine ylide by utilizing the characteristics of silicon: a facile route to pyrrolidines and pyrroles from α-silylimines bound to resin

The solid-phase synthesis of pyrrolidine and pyrrole derivatives using polymer-supported α-silylimines is described. Polymer-supported azomethine ylides were generated from the corresponding α-silylimine by thermal 1,2-silatropy onto the imino nitrogen or by treatment with a trifluorosilane as a quaternization and desilylation reagent, and the resulting species were then reacted with dipolarophiles to give five-membered heterocycles.

Unprecedented 1,4-stannatropy: effective generation of azomethine ylides as nitrile ylide equivalents from N-(stannylmethyl)thioamides

Generation and cycloaddition of less- or non-stabilized azomethine ylides, or nitrile ylide equivalents, via unprecedented 1,4-stannatropy of N-(tributylstannylmethyl)thioamides were achieved. The reactions with dipolarophiles, such as electron-deficient alkenes and alkynes, afforded corresponding pyrrolidine and pyrrole derivatives effectively.

Temperature dependent 1H NMR study of the substrate complex derived from zinc(II) perchlorate, (R,R)-4,6-dibenzofurandiyl-2,2′-bis(4-phenyloxazoline), and 3-acetyl-2-oxazolidinone. Evidence for octahedral structure of the substrate complex

Abstract Temperature dependent 1 H NMR study has been performed on the substrate complex derived from zinc(II) perchlorate, ( R , R )-4,6-dibenzofurandiyl-2,2′-bis(4-phenyloxazoline), and 3-acetyl-2-oxazolidinone in deuteriodichloromethane. At room temperature, two isomers of octahedral substrate complexes are rapidly exchanging through a trigonal bipyramid intermediate. Liberation of the DBFOX/Ph ligand from the substrate complex can not be observed in a wide range of temperature, showing high stability of the DBFOX/Ph·Zn(ClO 4 ) 2 complex.

A novel synthesis of silyl enol ethers from α-silylbenzylthiols and carboxylic acid derivatives via CC bond formation; thermal rearrangement of S-α-silylbenzyl thioesters

A new procedure for the synthesis of silyl enol ethers from S-α-silylbenzyl thioesters without need for either bases or catalysts via CC bond formation is described. Solutions of S-α-silylbenzyl thioesters were simply heated at 180°C for 24 h in a sealed tube to give silyl enol ethers in good yields with high stereoselectivity. Cyclization of the dipoles generated by thermal rearrangement of the silyl group and elimination of sulfur afforded silyl enol ethers.

Novel aziridination of olefins: direct synthesis from sulfonamides using t-BuOI

tert-Butyl hypoiodite (t-BuOI) was found to be a powerful reagent for synthesis of aziridines from olefins and sulfonamides. The aziridination of olefins was achieved by using sulfonamides with t-BuOI. Our preliminary findings represent the example of metal-free aziridination of olefins with readily accessible sulfonamides as a nitrogen source.

Direct synthesis of oxazolines from olefins and amides using t-BuOI

A new and simple method for the synthesis of oxazolines from readily accessible olefins and amides using tert-butyl hypoiodite is described; aromatic/aliphatic olefins and amides can be used in the reaction to give a variety of oxazolines.

A New Simple Method for the Synthesis of Thiophene Derivatives — Generation of Thiocarbonyl Ylides form S-a-(Dimethylphenylsilyl)benzyl Acylates and Their Cycloaddition with Acetylenic Dipolarophiles —

The cycloaddition of S-α-(dimethylphenylsilyl)benzyl acylates (1) with acetylenic dipolarophiles via 1,4-silatropy proceeded readily to afford thiophene derivatives. The reaction of thioesters (1) with 1-diethylamino-1-propyne (A), an electron-rich acetylenic dipolarophile, gave 5-aryl-3-diethylamino-4-methyl-2-phenylthiophenes (3) and 4-aryl-2-diethylamino-3-methyl-5-phenylthiophenes (4). When dimethyl acetylenedicarboxylate (DMAD), an electron-deficient alkyne, was used, the reaction of thioesters (1) afforded thiophene derivatives (4) exclusively.