Vinyl halides containing vinylic and allylic silane terminators undergo a stereospecific palladium(0)-catalyzed cross-coupling with derivatives of terminal propargylic and homopropargylic alcohols to polyunsaturated silanes. Basic stable and unstable protecting groups were tolerated under slightly different reaction conditions.
The use of rieke zinc metal in the selective reduction of alkynes
作者:Whe-Narn Chou、David L. Clark、James B. White
DOI:10.1016/s0040-4039(00)92612-1
日期:1991.1
Rieke zinc has been found to be a very selective reducing agent of alkynes to cis-alkenes, allowing for the reduction of enynes to 1,3-dienes, diynes to enynes or dienes, and of propargylic alcohols to cis-allylic
The use of trans-2,3-divinyl epoxides as precursors to carbonyl ylides
作者:Whe-Narn Chou、James B. White
DOI:10.1016/0040-4039(91)80552-h
日期:1991.12
3-Divinyl epoxides have been found to be good substrates for the generation of carbonylylides in CCl4 and 145 °C. These ylides, to a limited extent, undergo isomerization to cis-2,3-divinyl epoxides, leading to the isolation of 4,5-dihydrooxepins. Of greater potential usefulness is the finding that these ylides can be efficiently trapped in an intermolecular sense by a dipolarophile, leading to dihydrofurans
Pentacyclic Furanosteroids: The Synthesis of Potential Kinase Inhibitors Related to Viridin and Wortmannolone
作者:Yunhui Lang、Fabio E. S. Souza、Xinshe Xu、Nicholas J. Taylor、Abdeljalil Assoud、Russell Rodrigo
DOI:10.1021/jo900922q
日期:2009.8.7
A regiocontrolled intermolecular Diels−Alder reaction of an o-benzoquinone followed by an intramolecular nitrile oxide cyclization is employed to prepare the BCD fragment of viridin. The AE segment is attached to it by means of an intramolecular Diels−Alder reaction of an o-benzoquinone monoketal generated in situ from tricycle 15 and 5-trimethylsilyl-2E,4E-pentadienol 20. The silyl substituent at
Control over the relative stereochemistry at C4 and C5 of 4,5-dihydrooxepins through the Cope rearrangement of 2,3-divinyl epoxides and a conformational analysis of this ring system
作者:Whe Narn Chou、James B. White、William B. Smith
DOI:10.1021/ja00038a032
日期:1992.6
The Cope rearrangements of cis-2,3-divinyl epoxides was used to control the relative stereochemistry at C4 and C5 of 4,5-dihdrooxepins. Wadsworth-Horner-Emmons olefination of either (4E)-cis-2,3-epoxy-5-(trimethylsilyl)-4-pentenal (3) or (5E)-cis-3,4-epoxy-6-(trimethylsilyl)-5-hexen-2-one (4) provided the cis epoxides used in this study