Controlling Asymmetric Remote and Cascade 1,3-Dipolar Cycloaddition Reactions by Organocatalysis
作者:Pernille H. Poulsen、Stefania Vergura、Alicia Monleón、Danny Kaare Bech Jørgensen、Karl Anker Jørgensen
DOI:10.1021/jacs.6b03546
日期:2016.5.25
The regio- and stereoselective control of cycloaddition reactions to polyconjugated systems has been demonstrated by applying asymmetric organocatalysis. Reaction of 2,4-dienals with nitrones allows for a highly regio- and stereoselective 1,3-dipolarcycloaddition in the presence of an aminocatalyst. The first cycloaddition on the remote olefin can be followed either by a cascade reaction or by other
Diverse reactivity of nitrones towards electron deficient acetylenes
作者:Sandhya Radhamani、Rakesh Natarajan、Peruparampil A. Unnikrishnan、Sreedharan Prathapan、John P. Rappai
DOI:10.1039/c5nj00742a
日期:——
Depending on the nature of N- and C-substituents, nitrones exhibit diverse reactivity towards electron deficient acetylenes. Observed reactions include formal 1,3-dipolar cycloaddition and nucleophilic addition reactions. Possible involvement of zwitterionic intermediates and an unusual 1-aza-Cope rearrangement account for the generation of unexpected 1 : 1 adducts in the reaction of N-arylnitrones.
A switch of enantiofacial selectivity in chiral ytterbium-catalyzed 1,3-dipolar cycloaddition reactions
作者:Mikako Kawamura、Shū Kobayashi
DOI:10.1016/s0040-4039(99)00469-4
日期:1999.4
Synthesis of both enantiomers of the 1,3-dipolarcycloaddition adducts betweennitrones and alkenes has been achieved using the same chiral ytterbiumcatalyst choosing achiral additives, nitrone and MS 4A.