Highly stereoselective Michael addition of azlactones to electron-deficient triple bonds under P-spiro chiral iminophosphorane catalysis: importance of protonation pathway
作者:Daisuke Uraguchi、Yusuke Ueki、Atsushi Sugiyama、Takashi Ooi
DOI:10.1039/c2sc22027j
日期:——
geometrically divergent asymmetric Michael addition of azlactones to methyl propiolate has been achieved under the catalysis of P-spiro chiral triaminoiminophosphoranes. An uncommon O-protonation of the intermediary allenic enolate is proposed to rationalize geometric control and its validity is proven by the development of highly Z- and enantioselective Michael addition of azlactones to cyanoacetylene with
催化控制的,杂内酯在几何上发散的不对称迈克尔加成反应 丙酸甲酯在P-螺环手性三氨基亚氨基正膦的催化下已经获得了成功。提出了一种不常见的中间烯酸烯酸酯的O-质子化来合理的几何控制,并通过开发高度的Z-和对映选择性的a内酯的Michael加成证明了它的有效性。氰基乙炔 具有广泛的基材范围。