Regioselective formation of endo- and exo-cyclic enamines:: Both enantiomeric products accessible by the same chiral auxiliary

被引：13

作者：

Christoffers, J ^{[1
]}

Kreidler, B ^{[1
]}

Oertling, H ^{[1
]}

Unger, S ^{[1
]}

Frey, W ^{[1
]}

机构：

[1] Univ Stuttgart, Inst Organ Chem, D-70569 Stuttgart, Germany

来源：

SYNLETT | 2003年 / 04期

关键词：

chiral auxiliaries; copper; Michael additions; regioselectivity; stereoselectivity;

D O I：

10.1055/s-2003-37513

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

The copper-catalyzed conversion of exo-cyclic enamines 4a-c with methyl vinyl ketone (2) yields spirocyclic products 6a-c in a sequence of Michael and aldol reaction. The application of the chiral auxiliary L-valine diethylamide results in the formation of quaternary stereocenters with high enantiomeric excess. The configuration of intermediate imine 5a is determined to be S. Thus, exocyclic enamines 4 yield S-configured spiroketones 6, whereas, as shown for spiroketone ent-6c, reaction of endo-cyclic enamines such as I generates the opposite configuration in the products applying the same auxiliary L-valine diethylamide 9.

引用

页码：493 / 496

页数：4

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