Total Synthesis of <i>d</i>,<i>l</i>-Isospongiadiol: An Intramolecular Radical Cascade Approach to Furanoditerpenes
作者:Phillip A. Zoretic、Ming Wang、Yongzheng Zhang、Zhongqi Shen、Anthony A. Ribeiro
DOI:10.1021/jo951581r
日期:1996.1.1
A stereoselective oxidative free-radical cyclization of beta-keto ester polyenes 7 and 19 has been accomplished as a one-step entry to the tricarbocyclic synthons 8and 21 which contain five and six stereogenic centers, respectively. These key synthons possessing an axial carboethoxy group at C-4 were ultimately converted to the spongian skeleton (8--> 14 and 21 --> 25 -->14). The synthesis of d,l-isospongiadiol
Metalloporphyrin Cr(TPP)Cl-catalyzed Claisen rearrangement of simple aliphatic allyl vinyl ethers and its unique stereoselectivity
作者:Toshikatsu Takanami、Mikiko Hayashi、Kohji Suda
DOI:10.1016/j.tetlet.2005.02.136
日期:2005.4
The catalytic Z-selective Claisenrearrangement of simple aliphatic allyl vinyl ethers can be achieved using a chromium(III) porphyrin complex, Cr(TPP)Cl, as a catalyst: Cr(TPP)Cl significantly enhances reversal of E–Z selectivity in the thermalClaisenrearrangement of allyl vinyl ethers, especially, 4,5- and 4,6-disubstituted derivatives, at low catalyst loading.