Synthesis of 2,6-disubstituted dihydropyrans via an efficient BiBr3-initiated three component, one-pot cascade
作者:Robert J. Hinkle、Yajing Lian、Lee C. Speight、Heather E. Stevenson、Melissa M. Sprachman、Lauren A. Katkish、M. Christa Mattern
DOI:10.1016/j.tet.2009.06.083
日期:2009.8
The rapid synthesis of cis-2,6-disubstituted dihydropyrans is achieved in a three-component, one-pot cascade reaction. BiBr3-mediated addition of ketene silyl acetals or silyl enol ethers to β,γ-unsaturated cis-4-trimethylsilyl-3-butenal provides a Mukaiyama aldol adduct containing a vinylsilane moiety tethered to a silyl ether. Addition of a second aldehyde initiates a domino sequence involving intermolecular
顺式-2,6-二取代二氢吡喃的快速合成是通过三组分一锅级联反应实现的。BiBr 3介导的烯酮甲硅烷基缩醛或甲硅烷基烯醇醚与 β,γ-不饱和顺式-4-三甲基甲硅烷基-3-丁烯醛的加成提供含有与甲硅烷基醚相连的乙烯基硅烷部分的 Mukaiyama 醛醇加合物。添加第二个醛会引发多米诺骨牌序列,包括分子间加成,然后是分子内甲硅烷基修饰的樱井 (ISMS) 反应。该一锅反应的分离产率从 44% 到 80% 不等,并且所有化合物均以顺式非对映异构体形式分离(10 个实施例)。