The Yb(OTf)3-catalyzed [3+2] cycloaddition of donor–acceptorcyclopropanes with thiourea offers an efficient route to diverse 2-amino-4,5-dihydrothiophenes (up to 92% yield), in which optically active 2-amino-dihydrothiophenes can be produced from enantiomerically pure cyclopropanes. Thiourea, which is an odorless and cheap reagent, provides a CS double bond, serves as an amino source, and functions
RhII-Catalyzed Thermal Cyclopropanations of a Phenyliodonium Bis(carbomethoxy)methylide with Alkenes and Dienes
作者:Georgia Georgakopoulou、Christos Kalogiros、Lazaros P. Hadjiarapoglou
DOI:10.1055/s-2001-18750
日期:——
Iodonium ylide 2, derived from dimethyl malonate, undergoes facile thermal cycloaddition with alkenes and dienes catalyzed with Rh2(OAc)4 to form the corresponding cyclopropanedicarboxylates and vinylcyclopropanedicarboxylates, respectively, in excellent yields.
TfOH-Catalyzed Formal [3 + 2] Cycloaddition of Cyclopropane 1,1-Diesters with Nitriles
作者:Bo Cui、Jun Ren、Zhongwen Wang
DOI:10.1021/jo402383a
日期:2014.1.17
A triflic acid-catalyzed formal [3 + 2] cycloaddition of cyclopropane 1,1-diesters with nitriles was developed. This reaction was expeditious, and the scope of the substituents in both cyclopropanes and nitriles was broad. This supplies an efficient and practical method for the synthesis of 1-pyrrolines.