Bicyclodihydrosiloles were readily prepared from opticallyactive enyne compounds by a radical cascade reaction triggered by tris(trimethylsilyl)silane ((Me3Si)3SiH). The reaction was initiated by the addition of a silyl radical to an alpha,beta-unsaturated ester, forming an alpha-carbonyl radical that underwent radical cyclization to a terminal alkyne unit. The resulting vinyl radical attacked the silicon atom in an
通过由三(三甲基甲硅烷基)硅烷((Me3Si)3SiH)引发的自由基级联反应,可以很容易地从光学活性烯炔化合物制备双环二氢硅醇。该反应通过将甲硅烷基加入 α,β-不饱和酯引发,形成 α-羰基自由基,该自由基环化成末端炔单元。所得乙烯基自由基以 SHi 方式攻击硅原子,得到二氢硅酮。该反应优先形成双环硅氧烷的反式异构体,选择性约为 7:3 至 9:1。
Gold(I)-Catalyzed Synthesis of Optically Active 1,4-Oxazepan-7-ones
作者:Akio Kamimura、Yu Yamane、Ryuichiro Yo、Toshiyuki Tanaka、Hidemitsu Uno
DOI:10.1021/jo501254x
日期:2014.8.15
Optically active seven-membered lactones, dimethyleneoxazepanones, were readily prepared in good yields from chiral beta-(N-propargylic)-amino-alpha-methylene carboxylic add tert-butyl esters in the presence of catalytic amounts of Ph3PAuCl and Cu(OTf)(2) A smooth 7-exo-dig cyclization was observed.