Chiral Oxazaborolidine−Aluminum Bromide Complexes Are Unusually Powerful and Effective Catalysts for Enantioselective Diels−Alder Reactions
作者:Duan Liu、Eda Canales、E. J. Corey
DOI:10.1021/ja068637r
日期:2007.2.1
acid catalyst than protonated 1 (i.e., 2) for enantioselectiveDiels−Alderreactions. Only 4 mol % of catalyst 3 is required to achieve yields and enantiomeric purities of 90% over a broad range of achiraldienes and dienophiles. The ligand from which 3 is derived can be recovered easily and with high efficiency. The method is illustrated by 22 examples.
Asymmetric Diels−Alder Reactions Catalyzed by a Triflic Acid Activated Chiral Oxazaborolidine
作者:E. J. Corey、Takanori Shibata、Thomas W. Lee
DOI:10.1021/ja025848x
日期:2002.4.1
generation of chiral Lewis superacids by protonation of a non-Lewis acidic oxazaborolidine (1) with triflic acid. The resulting cationic species (3) are powerful and highly enantioselective catalysts for the Diels-Alder reaction of various 1,3-dienes with alpha,beta-enals. An optimization study (see Table 1) led to the selection of reaction conditions and catalysts (6A and 6B) which are very effective. The
Catalytic Enantioselective Diels−Alder Reaction via a Chiral Indium(III) Complex
作者:Yong-Chua Teo、Teck-Peng Loh
DOI:10.1021/ol050518d
日期:2005.6.1
A chiral indium complex has been developed to effect high enantioselectivities in catalyzing enantioselective Diels-Alder reaction. The cycloaddition of a variety of cyclic and open-chained dienes to 2-methacrolein and 2-bromoacrolein resulted in good yields and excellent enantioselectivities (up to 98% ee).
Catalytic Enantioselective Diels−Alder Reaction in Ionic Liquid via a Recyclable Chiral In(III) Complex
作者:Fan Fu、Yong-Chua Teo、Teck-Peng Loh
DOI:10.1021/ol062481i
日期:2006.12.1
A recyclable, air-and moisture- stable chiral indium complex in [hmim][ PF6-] ionic liquid has been developed. The cycloaddition of a variety of cyclic and open- chained dienes to 2-methacrolein and 2- bromoacrolein resulted in good yields and excellent enantioselectivities ( up to 98% ee). Moreover, the chiral In( III) complex can be reused for seven successive cycles with comparable enantioselectivities and yields without loss of catalytic activity.