Acid-Catalyzed Intramolecular [2+2] Cycloaddition of Ene-allenones: Facile Access to Bicyclo[<i>n</i>.2.0] Frameworks
作者:Jun-Feng Zhao、Teck-Peng Loh
DOI:10.1002/anie.200902471
日期:2009.9.14
Two plus two equals a bicycle: A highly efficient acid‐catalyzed intramolecular [2+2] cycloaddition of ene‐allenones affords strained bicyclo[n.2.0] frameworks, which contain vicinal all‐carbon quaternary and tertiary centers (see scheme; Tf: trifluoromethanesulfonyl), under mild conditions with excellent yields and chemo‐, regio‐, and diastereoselectivities.
Asymmetric Syntheses of 8-Oxabicyclo[3,2,1]octanes: A Cationic Cascade Cyclization
作者:Bin Li、Yu-Jun Zhao、Yin-Chang Lai、Teck-Peng Loh
DOI:10.1002/anie.201202699
日期:2012.8.6
High octane: A novel and practical syntheses of 8‐oxabicyclo[3.2.1]octanes using a cationic cascade cyclization reaction has been developed (see scheme; TIPS=triisopropylsilyl). The diastereomer of the cyclization product isolated depends upon whether the acetal or aldehyde substrate is used.