1-Silyl-1-boryl-2-alkenes: Reagents for Stereodivergent Allylation Leading to 4-Oxy-(E)-1-alkenylboronates and 4-Oxy-(Z)-1-alkenylsilanes
摘要:
Silylboryl reagents for organic synthesis: 1-silyl-1-boryl-2-alkenes (2) were prepared efficiently by gem-silylborylation of α-chloroallyllithium compounds from (dimethylphenylsilyl)(pinacolato)borane (1; see scheme, LDA=lithium diisopropylamide) and were demonstrated to allylate acetals and aldehydes in the presence of a Lewis acid to produce (E)-4-alkoxy-alkenylboronates. Heating the reagents with aldehydes in the absence of Lewis acid afforded (Z)-4-hydroxy-alkenylsilanes stereospecifically.
Silylboryl reagents for organic synthesis: 1-silyl-1-boryl-2-alkenes (2) were prepared efficiently by gem-silylborylation of α-chloroallyllithium compounds from (dimethylphenylsilyl)(pinacolato)borane (1; see scheme, LDA=lithium diisopropylamide) and were demonstrated to allylate acetals and aldehydes in the presence of a Lewis acid to produce (E)-4-alkoxy-alkenylboronates. Heating the reagents with aldehydes in the absence of Lewis acid afforded (Z)-4-hydroxy-alkenylsilanes stereospecifically.
Kinetic Resolution of α‐Silyl‐Substituted Allylboronate Esters via Chemo‐ and Stereoselective Allylboration of Aldehydes
作者:Jinyoung Park、Yongsuk Jung、Jeongho Kim、Eunsung Lee、Sarah Yunmi Lee、Seung Hwan Cho
DOI:10.1002/adsc.202001170
日期:2021.4.27
We describe the kinetic resolution of α‐silyl‐substituted allylboronate esters via chiral phosphoric acid‐catalyzed chemo‐, diastereo‐ and enantioselective allylboration of aldehydes. This process provides two synthetically versatile enantioenriched compounds, (Z)‐δ‐silyl‐substituted anti‐homoallylic alcohols and α‐silyl‐substituted allylboronate esters, with a selectivity factor up to 328. We propose