An external chiral ligand controlled enantioselective opening of oxirane and oxetane by organolithiums
摘要:
Enantioselective nucleophilic opening reactions of cyclohexene oxide and 3-phenyloxetane were achieved by the combination of an external chiral ligand and organolithiums in the presence of boron trifluoride to give the corresponding alcohols in up to 47% ee. (C) 1997 Elsevier Science Ltd.
An external chiral ligand controlled enantioselective opening of oxirane and oxetane by organolithiums
摘要:
Enantioselective nucleophilic opening reactions of cyclohexene oxide and 3-phenyloxetane were achieved by the combination of an external chiral ligand and organolithiums in the presence of boron trifluoride to give the corresponding alcohols in up to 47% ee. (C) 1997 Elsevier Science Ltd.
Catalytic Asymmetric Bromine-Lithium Exchange: A New Tool to Build Axial Chirality
作者:Quentin Perron、Alexandre Alexakis
DOI:10.1002/adsc.201000517
日期:2010.10.4
We present here the first catalytic desymmetrization of the 2,2′,6,6′-tetrabromobiphenyl 1 and analogues, by a bromine-lithiumexchange catalyzed by either diamines or diether derivatives (0.5 equiv.), yielding axiallychiral compounds in high yield (up to 89%) and high enantioselectivity (up to 82%).