Optically Pure α-(Trimethylsilyl)benzyl Alcohol: A Practical Chiral Auxiliary for Oxocarbenium Ion Reactions
摘要:
GRAPHICSEnantiopure (S)-alpha-(trimethylsilyl)benzyl alcohol (98% ee) was prepared by Noyori's transfer hydrogenation of benzoyltrimethylsilane. The corresponding trimethylsilyl ether was subjected to Marko's silyl modified Sakurai conditions with a variety of aldehydes to afford homoallylic ethers in high diastereoselectivity. The practicality of the alpha-trimethylsilyl benzyl group as an oxocarbenium ion auxiliary was further demonstrated by its efficient deprotection or conversion to a benzyl protecting group.
We have successfully developed the asymmetric hydrogenation of β‐silyl‐α,β‐unsaturatedesters to prepare chiral 3‐substituted‐3‐silylpropionic esterproducts catalyzed by rhodium/bisphosphine‐thiourea (ZhaoPhos) with excellent results (up to 97% yield, >99% ee, 1500 TON). Moreover, our hydrogenation products can be efficiently converted to other important organic molecules, such as chiral ethyl (R
Hauser; Hance, Journal of the American Chemical Society, 1952, vol. 74, p. 5091,5094,5095
作者:Hauser、Hance
DOI:——
日期:——
Preparation and Reactions of α-Halo Derivatives of Certain Tetra-substituted Hydrocarbon Silanes. Grignard Syntheses of Some Silyl Compounds<sup>1</sup>