Developing a Diastereoselective Intramolecular [4 + 3] Cycloaddition of Nitrogen-Stabilized Oxyallyl Cations Derived from <i>N</i>-Sulfonyl-Substituted Allenamides
作者:Andrew G. Lohse、Richard P. Hsung、Mitchell D. Leider、Sunil K. Ghosh
DOI:10.1021/jo200147h
日期:2011.5.6
Efforts toward achieving a practical and diastereoselective intramolecular [4 + 3] cycloaddition of nitrogen-stabilizedoxyallylcations with tethered dienes are described. Epoxidation of N-sulfonyl substituted allenamides with dimethyldioxirane (DMDO) generates nitrogen-stabilizedoxyallylcations that readily undergo stereoselective [4 + 3] cycloaddition with dienes. Selectivity is found to depend
Thermal Intramolecular [4 + 2] Cycloadditions of Allenamides: A Stereoselective Tandem Propargyl Amide Isomerization−Cycloaddition
作者:Andrew G. Lohse、Richard P. Hsung
DOI:10.1021/ol901283m
日期:2009.8.6
A stereoselective intramolecular normal demand [4 + 2] cycloaddition of allenamides under thermal conditions without metal assistance is described. This work led to the development of a stereoselective tandem propargyl amide-isomerization−[4 + 2] cycloaddition sequence amenable for rapid assembly of complex nitrogen heterocycles.