Annulations of Enantioenriched Allenylsilanes with in Situ Generated Iminium Ions: Stereoselective Synthesis of Diverse Heterocycles
作者:Ryan A. Brawn、James S. Panek
DOI:10.1021/ol802618p
日期:2009.1.15
mediated annulations with in situ generated iminium ions derived from tert-butyl carbamate and methyl carbamate to selectively form functionalized 4,5-dihydropyrroles and 4,5-dihyrooxazines, respectively. The dihydropyrrole products were further elaborated in a stereocontrolled vinylsilane terminated cyclization with in situ generated oxonium ions, resulting in pyranopyrroles.
高度对映体富集的
丙二烯基
硅烷参与
路易斯酸介导的环化,原位生成的
亚胺离子源自
氨基甲酸叔丁酯和
氨基甲酸甲酯,分别选择性地形成功能化的 4,5-二氢
吡咯和 4,5-二氢恶嗪。二氢
吡咯产物在立体控制的
乙烯基硅烷封端环化中进一步加工,原位生成氧鎓离子,产生
吡咯并
吡咯。