Replacing trifluoroacetic acid with it catalytic amount of Lewis acid in the osmium mediated oxidative cyclization results in higher yielding reactions that can proceed nearly an order of magnitude faster. The osmium loading can also be reduced to as little its 0.2 mol %. Furthermore, these mildly acidic conditions are capable of tolerating a wide range of acid sensitive protecting groups that are incompatible with previous cyclization conditions.
A General Oxidative Cyclization of 1,5-Dienes Using Catalytic Osmium Tetroxide
作者:Timothy J. Donohoe、Sam Butterworth
DOI:10.1002/anie.200390253
日期:2003.2.24
Oxidative Cyclization of Diols Derived from 1,5-Dienes: Formation of Enantiopurecis-Tetrahydrofurans by Using Catalytic Osmium Tetroxide; Formal Synthesis of (+)-cis-Solamin
作者:Timothy J. Donohoe、Sam Butterworth
DOI:10.1002/anie.200500513
日期:2005.7.25
A Lewis Acid Promoted Oxidative Cyclization
作者:Timothy J. Donohoe、Paul C. M. Winship、Daryl S. Walter
DOI:10.1021/jo901243y
日期:2009.8.21
Replacing trifluoroacetic acid with it catalytic amount of Lewis acid in the osmium mediated oxidative cyclization results in higher yielding reactions that can proceed nearly an order of magnitude faster. The osmium loading can also be reduced to as little its 0.2 mol %. Furthermore, these mildly acidic conditions are capable of tolerating a wide range of acid sensitive protecting groups that are incompatible with previous cyclization conditions.