Intramolecular Addition of Nucleophilic Carbenes to Acceptor-Substituted Alkenyl Groups: Synthesis and transformation of homobenzofurans and synthesis of a homoindole
作者:Chunbao Li、Andrea Vasella
DOI:10.1002/hlca.19930760114
日期:1993.2.10
The intramolecular addition of unsaturated alkoxycarbenes leads in high yields and diastereoselectively to fused cyclopropanes (Scheme 1). Reaction of the halodiazirines 2, 10, 11, and 20 with the unsaturated phenolates 1, 8, and 9 yielded intermediate alkoxydiazirines, and hence the homobenzofurans 5, 12–16, 22, and 26 (Scheme 2). The intermediate alkoxydiazirine 25 was isolated at low temperature
分子内添加不饱和烷氧基卡宾导致高产率并且非对映选择性地产生稠合的环丙烷(方案1)。所述halodiazirines的反应2,10,11,和20与不饱和酚1,8,和9个得到中间alkoxydiazirines,因此homobenzofurans 5,12 - 16,22,和26(方案2)。在低温下分离出中间体烷氧基二嗪25(方案3)。环丙烷衍生物12和27以及14和28之间的平衡建立在120°。在200°,通过环丙烷环的旋旋打开,然后将其电环化,将12重排至色烯29。的氢化29,得到(清一色顺式) -苯并二氢吡喃32(方案4)。推测通过34和10的S RN 1反应以高收率获得均吲哚35(方案5)。