<i>exo′</i>
‐Selective Construction of Spirobipyrrolidines by the Silver‐catalyzed Asymmetric [3+2] Cycloaddition of Imino Esters with 4‐Benzylidene‐2,3‐dioxopyrrolidines
exo′-selective [3+2] cycloaddition of imino esters with 4-benzylidene-2,3-dioxopyrrolidines is described. The reaction was efficiently catalyzed by AgOAc/(R, Sp)-ThioClickFerrophos (TCF) to afford spirobipyrrolidines in excellent enantio- and diastereoselectivities. Mechanistic studies suggested that the unusual exo′-selectivity is due to a stepwise Michael addition/Mannich sequence with bond rotation.
描述了史无前例的 Ag 催化的 外'-选择性 [3+2]亚氨基酯与 4-benzylidene-2,3-dioxopyrrolidines 的环加成反应。该反应被 AgOAc/( R , S p )-ThioClickFerrophos (TCF) 有效催化,得到具有优异对映选择性和非对映选择性的螺双吡咯烷。机理研究表明,不寻常的exo '-选择性是由于具有键旋转的逐步迈克尔加成/曼尼希序列。
Palladium-catalyzed reduction of an allylic amine : a formal access to both diastereoisomers of cyclopentenyl glycine
作者:Aude Bourgeois-Cury、Dong Doan、Jacques Gore
DOI:10.1016/s0040-4039(00)91600-9
日期:1992.3
The easily accessible bicyclic amines 3 (exo or endo) are regioselectively transformed to the methyl esters of the diastereoisomers (1c or 1d) of N-benzyl cyclopentenyl glycine by reaction with hydride donors (mainly NaBH3CN) in the presence of a palladium(0) catalyst.