Reprint of: Enantiodivergent hydroboration reactions of a racemic allenylsilane with diisopinocampheylborane and Curtin–Hammett controlled double asymmetric crotylboration reactions of (S)-E-α-phenyldimethylsilyl(ddiisopinocampheyl)-crotylborane
作者:Ming Chen、William R. Roush
DOI:10.1016/j.tet.2013.06.053
日期:2013.9
The enantiodivergent hydroboration reactions of racemic allenylsilane (+/-)-4 with ((d)Ipc)(2)BH and subsequent crotylboration of achiral aldehydes with the product crotylborane (S)-E-5 at -78 degrees C provide (E)-delta-silyl-anti-homoallylic alcohols 6 in 71-89% yield and with 93-96% ee. Intriguingly, mismatched double asymmetric crotylboration reactions of enantioenriched chiral aldehydes 20 with (S)-E-5 proceed under Curtin-Hammett control to give anti-beta-hydroxylcrotylsilanes 24 as the only products. (C) 2013 Elsevier Ltd. All rights reserved.