Ultrasound-Promoted synthesis of substituted phenanthrene-1,4-quinones; the structure of plectranthon D
摘要:
A series of tanshinone-type diterpenoids was prepared by ultrasound-promoted and Lewis acid catalyzed, highly regioselective cycloadditions of styrenes with substituted 1,4-benzoquinones as the key step.
Short, Enantioselective Total Synthesis of Aflatoxin B<sub>2</sub> Using an Asymmetric [3+2]-Cycloaddition Step
作者:Gang Zhou、E. J. Corey
DOI:10.1021/ja054503m
日期:2005.8.1
A highly enantioselective [3+2]-cycloaddition reaction of 2,3-dihydrofuran with 1,4-benzoquinones using a chiral oxazaborolidinium triflimidate as catalyst has been developed which allows rapid access to a variety of chiral phenolic tricycles (enantiomeric excesses ranging from 91 to 98%). The utility of this new methodology is demonstrated by a shortsynthesis of the important pentacyclic natural
A series of tanshinone-type diterpenoids was prepared by ultrasound-promoted and Lewis acid catalyzed, highly regioselective cycloadditions of styrenes with substituted 1,4-benzoquinones as the key step.