Enantiodivergent Hydroboration Reactions of a Racemic Allenylsilane with Diisopinocampheylborane and Curtin-Hammett Controlled Double Asymmetric Crotylboration Reactions of (S)-E-α-phenyldimethylsilyl( (d) diisopinocampheyl)-crotylborane.

Abstract

The enantiodivergent hydroboration reactions of racemic allenylsilane (±)-4 with ( (d) Ipc)2BH and subsequent crotylboration of achiral aldehydes with the product crotylborane (S)-E-5 at -78 °C provide (E)-δ-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-3-hydroxylcrotylsilanes 24 as the only products.

Cite this paper

@article{Chen2013EnantiodivergentHR, title={Enantiodivergent Hydroboration Reactions of a Racemic Allenylsilane with Diisopinocampheylborane and Curtin-Hammett Controlled Double Asymmetric Crotylboration Reactions of (S)-E-α-phenyldimethylsilyl( (d) diisopinocampheyl)-crotylborane.}, author={Ming Chen and William R Roush}, journal={Tetrahedron}, year={2013}, volume={69 36}, pages={7551-7558} }