Regioselective 1,4- over 1,2-addition of 3,3-bis(silyl) allyloxy lithium to enals, enones and enoates. The remarkable α-effect of silicon.
A remarkable α-effect of silicon has been discovered that results in soft nucleophilicity at the Cγ of 3,3-bis(silyl) allyloxy lithium 1. The addition of 1 to α,β-unsaturated carbonyl compounds, including enals, proceeds in a 1,4- over 1,2-manner with medium to good regioselectivity, whereas the parent allyloxy lithium 4 undergoes complete 1,2-addition. The results from DFT calculations of HMPAcomplexed 1 and 4 provide the rationale to explain this different regioselectivity.
Key laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, West China School of Pharmacy, Sichuan University, Chengdu, 610041, China. zhenleisong@scu.edu.cn.
Xincui
X
Ye
Xianwei
X
Sun
Zhenggang
Z
Huang
Na
N
Yang
Zhishan
Z
Su
Changwei
C
Hu
Zhenlei
Z
Song
D000838:Anions; D002845:Chromatography; D007659:Ketones / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry*; D008958:Models, Molecular; D066244:Proton Magnetic Resonance Spectroscopy; D012825:Silicon / Q000737:chemistry*; D013237:Stereoisomerism
D000838:Anions; D007659:Ketones; D008094:Lithium; D012825:Silicon