Enantioselective synthesis of chiral α,β-unsaturated γ-substituted butyrolactams by organocatalyzed direct asymmetric vinylogous Michael addition of α,β-unsaturated γ-butyrolactam to 2-enoylpyridines
organocatalyzed direct asymmetric vinylogous Michaeladdition reaction of α,β-unsaturated γ-butyrolactam to 2-enoylpyridines has been developed with a chiral bifunctional amine-squaramide as the catalyst. This approach provides easy access to a series of optically active α,β-unsaturated γ-substituted butyrolactams in high yields (up to 99%) with excellent diastereoselectivities (up to >99 : 1) and enantioselectivities
effective asymmetriccatalysts (0.5–5.0 mol % catalyst loading) for a variety of reactions with α,β‐unsaturated carbonyl compounds, namely Friedel–Crafts alkylations (94–99 % ee), Michael additions with CH‐acidic compounds (81–97 % ee), and a variety of cycloadditions (92–99 % ee with high d.r.). Mechanistic investigations and crystal structures of an iridium‐coordinated substrates and iridium‐coordinated
Phosphine-mediated enantioselective [1 + 4]-annulation of Morita–Baylis–Hillman carbonates with 2-enoylpyridines
作者:Tao Wang、Pengfei Zhang、Wenjun Li、Pengfei Li
DOI:10.1039/c8ra09453e
日期:——
This work describes a phosphine-catalyzedasymmetric [1 + 4] annulation of Morita–Baylis–Hillman carbonates with 2-enoylpyridines for constructing the enantiomerically enriched 2,3-dihydrofuran motif. In the presence of (−)-1,2-bis[(2R,5R)-2,5-dimethylphospholano]benzene, a series of Morita–Baylis–Hillman carbonates reacted with 2-enoylpyridines smoothly to afford a wide range of optically active 2
这项工作描述了膦催化的 Morita-Baylis-Hillman 碳酸盐与 2-烯酰基吡啶的不对称 [1 + 4] 环化,用于构建对映体富集的 2,3-二氢呋喃基序。在 (-)-1,2-bis[(2 R ,5 R )-2,5-dimethylphospholano]苯存在下,一系列 Morita-Baylis-Hillman 碳酸盐与 2-烯酰基吡啶顺利反应得到宽范围具有吡啶基序的光学活性 2,3-二氢呋喃的高产率和出色的不对称诱导。