Trimethylsilyltriflate-Promoted Addition of 2-Trimethylsilyloxyfuran to a Chiral Cyclic Nitrone; a Short Synthesis of [1S(1α,2β,7β,8α,8aα)]-1,2-Di(t-butyldiphenylsilyloxy)-indolizidine-7,8-diol
作者:Marco Lombardo、Claudio Trombini
DOI:10.1016/s0040-4020(99)01001-7
日期:2000.1
The trimethylsilyl triflate promoted addition of 2-trimethylsilyloxyfuran to (3S,4S)-3,4-dihydro-3,4-di(t-butyldiphenylsilyloxy)-2H-pyrrole 1-oxide, derived from (R,R)-tartaric acid, displays complete facial selectivity, affording two diastereomeric butenolides in excellent overall yield. The major adduct undergoes silica-gel induced ring-closure to give in almost quantitative yield [4S(4α,5β,5aβ,5bα
三甲基甲硅烷,三氟甲磺酸促进加入2- trimethylsilyloxyfuran至(3小号,4小号)-3,4-二氢-3,4-二(吨-butyldiphenylsilyloxy)-2H-吡咯-1-氧化物,从(派生- [R ,- [R ) -酒石酸显示出完全的面部选择性,以优异的总收率提供了两种非对映异构的丁烯内酯。主要加合物经历硅胶诱导的闭环反应,得到几乎定量的产率[4 S(4α,5β,5aβ,5bα,8aα)]-六氢-4,5-二(叔丁基二苯基甲硅烷氧基)-吡咯[1, 2- b ]呋喃并[2,3 d ]异恶唑-7-(3H)酮; 用DIBAH还原,然后在Pd(OH)2上进行氢解/ C提供部分保护的1,2,7,8-吲哚并咪唑四醇。