Reductive Radical Cyclisations of Bromo Acetals and (Bromomethyl)silyl Ethers of Terpenoid Alcohols
作者:Edward R. Lee、Ivo Lakomy、Peter Bigler、Rolf Scheffold
DOI:10.1002/hlca.19910740117
日期:1991.1.30
The tin hydride promoted and the reductive vitamin B12 catalysed radical cyclisation of mixed 2-bromo-acetaldehyde acetals and of (2-bromomethyl)dimethylsilyl ethers of allylic terpenoid alcohols has been investigated: 3-oxadeca-5,9-dien-l-yl radicals undergo 5-‘exo’ cyclisation to oxolanes (Scheme 4), 3-oxa-2-siladeca-5,9-dien-1-yl radicals sequential 6-‘endo’5-‘exo’ tandem cyclisation to cis-3-oxa-4-silabicyclo[4
已经研究了氢化锡的促进作用,并研究了还原性维生素B 12催化混合的2-溴-乙醛缩醛和烯丙基萜烯醇的(2-溴甲基)二甲基甲硅烷基醚的自由基环化:3-oxadeca-5,9-dien-l-基的基团经历5-“外切‘环化氧杂环戊烷(方案4),3-氧杂-2- siladeca -5,9-二烯-1-基的基团顺序6-’内切‘5-’外切”串联环化成顺式- 3-oxa-4-silabicyclo [4.3.0]壬烷(方案5)和3-oxa-2-silatetradeca-5,9,13-trien-1-yl自由基顺序6-'内切'6-'内切' 5- 'exo '三联环化成反式-transoid -反式- 12-氧杂-11- silatricyclo [7.4.0.0 2,6 ]十三烷(方案6)。