Asymmetric Catalytic Enantio- and Diastereoselective Boron Conjugate Addition Reactions of α-Functionalized α,β-Unsaturated Carbonyl Substrates
作者:Jian-Bo Xie、Siqi Lin、Shuo Qiao、Guigen Li
DOI:10.1021/acs.orglett.6b01998
日期:2016.8.5
established for the asymmetric boron conjugate addition of B2pin2 onto α-functionalized (involving C, N, O, and Cl) α,β-unsaturated carbonyls under mild, neutral conditions involving Cu[(S)-(R)-ppfa]Cl, AgNTf2, and alcohols. The dual additives of AgNTf2 and alcohols were found to play crucial roles for achieving high catalytic activity and enantio- and diastereoselectivity (up to 98% ee and 70:1 dr).
The Bifunctional Silyl Reagent Me
<sub>2</sub>
(CH
<sub>2</sub>
Cl)SiCF
<sub>3</sub>
Enables Highly Enantioselective Ketone Trifluoromethylation and Related Tandem Processes
A novel bifunctional trifluoromethylsilyl reagent (BTR), Me2(CH2Cl)SiCF3 is prepared, which enablesketonetrifluoromethylations with excellent enantioselectivity and broad scope. Notably, by taking advantage of the chloromethyl group, a tandem synthesis of chiral trifluoromethylated oxasilacyclopentanes and α-CF3 tertiary alcohols with vicinal tertiary or quaternary stereocenters was developed.