Stereoselective Synthesis of Five-Membered Spirooxindoles through Tomita Zipper Cyclization
作者:D. B. Ramachary、Chintalapudi Venkaiah、Patoju M. Krishna
DOI:10.1021/ol4020305
日期:2013.9.20
Functionalized five-membered spirooxindoles were furnished in good yields and excellent stereoselectivities by using an effective Tomita zipper cyclization (TZC) reaction through organophosphine catalysis.
Divergent Cyclization Reactions of Morita–Baylis–Hillman Carbonates of 2-Cyclohexenone and Isatylidene Malononitriles
作者:Jing Peng、Guang-Yao Ran、Wei Du、Ying-Chun Chen
DOI:10.1021/acs.orglett.5b02157
日期:2015.9.18
Zwitterionic dienolates generated from Morita-Baylis-Hillman carbonates of cyclohexen-2-one and a phenolic tertiary amine catalyst underwent divergent cyclization reactions with isatylidene malononitriles. A new [4 + 2] stepwise cyclization process was disclosed to deliver complex bridged spirooxindoles after the initial delta'-regioselective Rauhut-Currier-type reaction with N-methyl electrophiles by the catalysis of beta-isocupreidine, while spirooxindoles incorporating an aromatic chromene motif were generated with N-MOM acceptors in the presence of alpha-isocupreine through different domino transformations.