Takashi Ohshima

Acylation of alcohols and amines is one of the most fundamental reactions. Due to the greater nucleophilicity of the amino group compared to the hydroxyl group, complete N-acylation occurs. Only an enzymatic reaction can promote a highly selective O-acylation reaction, and there are no examples using an artificial catalyst. Here we report that the tetranuclear zinc cluster Zn4(OCOCF3)6O efficiently catalyzes highly chemoselective O-acylation in the presence of primary and secondary alkyl amines.

Transition metal-catalyzed amination of allylic compounds via a pi-allylmetal intermediate is a powerful and useful method for synthesizing allylamines. Direct catalytic substitution of allylic alcohols, which forms water as the sole coproduct, has recently attracted attention for its environmental and economical advantages. Here, we describe the development of a versatile direct catalytic amination of both aryl- and alkyl-substituted allylic alcohols with various amines using Pt-Xantphos and Pt

Optically active α,β-diamino acids are prepared under asymmetric phase-transfer reaction conditions from a glycine Schiff base and N-protected imines with a tartrate-derived diammonium salt (TaDiAS) as the phase-transfer catalyst (see scheme; Boc=tert-butoxycarbonyl). Chemoselective deprotection of the N atoms allows straightforward transformations of the α,β-diamino acid products to be carried out.

An asymmetric Heck reaction−carbanion capture process was realized for the first time, making possible the catalytic asymmetric synthesis of various functionalized bicyclo[3.3.0]octane derivatives 6 in up to 94% ee. Sodium bromide had interesting effects on this asymmetric Heck reaction−carbanion capture process, and these effects were useful for improving the enantiomeric excess. Furthermore, the catalytic asymmetric synthesis of (−)-Δ9(12)-capnellene (7) was achieved for the first time, using

The enantioselective total synthesis of (-)-strychnine was accomplished through the use of the highly practical catalytic asymmetric Michael reaction (0.1 mol % of (R)-ALB, more than kilogram scale, without chromatography, 91% yield and >99% ee) as well as a tandem cyclization that simultaneously constructed B- and D-rings (>77% yield). Moreover, newly developed reaction conditions for thionium ion cyclization, NaBH3CN reduction of the imine moiety in the presence of Lewis acid to prevent ring o

A simple NaOMe catalyst provides superior accessibility to a wide variety of functionalized amides including peptides through direct amination of esters in an atom-economical and environmentally benign way.

Thinking outside the box: A newly developed C1-symmetric Rh/Phebox complex efficiently catalyzed the asymmetric alkynylation of α-ketoester 1 with various aryl and alkyl substituted terminal alkynes to provide the corresponding chiral tertiary propargylic alcohols with up to 99 % ee (see scheme; TMS=trimethylsilyl).

Direct amination of unactivated allylic alcohols with aqueous ammonia was catalyzed by a Pt/phosphine complex to give the corresponding allylamines along with water as the sole by-product. Under optimized reaction conditions, primary allylamines were obtained as major products with excellent monoallylation selectivity. cod=1,5-cyclooctadiene. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or type