The synthesis of novel chiral propargylic epoxides ((R)-1-t-butyldimethylsilyl-3,4-epoxy-1-butyne, (3S,4S)-3,4-epoxy-1-octyne, (3R,4S)-1-t-butyldimethylsilyl-3,4-epoxy-l-pentyne) has been developed starting from the readily available tartaric acid derivative, (S,S)-(+)-2,3-O-isopropylidene-L-threitol. (C) 1998 Elsevier Science Ltd. All rights reserved.
Highly Selective Hydrolytic Kinetic Resolution of Terminal Epoxides Catalyzed by Chiral (salen)Co<sup>III</sup> Complexes. Practical Synthesis of Enantioenriched Terminal Epoxides and 1,2-Diols
作者:Scott E. Schaus、Bridget D. Brandes、Jay F. Larrow、Makoto Tokunaga、Karl B. Hansen、Alexandra E. Gould、Michael E. Furrow、Eric N. Jacobsen
DOI:10.1021/ja016737l
日期:2002.2.1
The hydrolytickineticresolution (HKR) of terminal epoxides catalyzed by chiral (salen)Co(III) complex 1 x OAc affords both recovered unreacted epoxide and 1,2-diol product in highly enantioenriched form. As such, the HKR provides general access to useful, highly enantioenriched chiral building blocks that are otherwise difficult to access, from inexpensive racemic materials. The reaction has several
Synthesis of a novel four-carbon chiron - (R)-1-t-butyldimethylsilyl-3, 4-epoxy-but- 1-yne
作者:Margus Lopp、Tonis Kanger、Anne Miiraus、Tonis Pehka、Ülo Lille
DOI:10.1016/s0957-4166(00)86131-5
日期:1991.1
A simple and efficient synthesis of the novel chiron-(R)-1-Tl3DMS-3,4-epoxybut-1-yne has been developed starting from a derivative of (R,R)-(+)-tartaricacid. A new stereoselective bromination reaction of an O-silyl ether with BBr3 is also described.
Enantioselective hydrogenation of alkynyl ketones catalyzed by Ru(OTf)(TsDPEN)(eta(6)-p-cymene) (TsDPEN = N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine) affords the propargylic alcohols in up to 97% ee. The alkynyl moieties are left intact In most cases. The reaction can be conducted with a substrate-to-catalyst molar ratio as high as 5000 under 10 atm of H-2. The mode of enantioselection is elucidated with the transition state models directed by the CH/pi attractive interaction between the substrate and the catalytic species.
A new synthesis of HMG-CoA reductase inhibitor NK-104 through hydrosilylation-cross coupling reaction