Access to Spirocyclic Oxindoles via N-Heterocyclic Carbene-Catalyzed Reactions of Enals and Oxindole-Derived α,β-Unsaturated Imines
摘要:
A diastereoselective access to beta-lactam fused spirocyclic oxindoles and related compounds bearing all carbon spiro centers is described. This N-heterocyclic carbene-catalyzed process employed challenging beta,beta-disubstituted alpha,beta-unsaturated imines to react with enals.
Access to Spirocyclic Oxindoles via N-Heterocyclic Carbene-Catalyzed Reactions of Enals and Oxindole-Derived α,β-Unsaturated Imines
作者:Kun Jiang、Bhoopendra Tiwari、Yonggui Robin Chi
DOI:10.1021/ol3008028
日期:2012.5.4
A diastereoselective access to beta-lactam fused spirocyclic oxindoles and related compounds bearing all carbon spiro centers is described. This N-heterocyclic carbene-catalyzed process employed challenging beta,beta-disubstituted alpha,beta-unsaturated imines to react with enals.
An easy lewis acid-mediated isomerization from (E)- to (Z)-Oxoindolin-3-ylidene ketones.
(E)-2-Oxoindolin-3-ylidene ketones can be easily isomerized to their (Z)-isomers by AlCl3 at room temperature in CH2Cl2. The behaviour of the unsaturated dicarbonyl framework in the (Z)-configuration as a bidentate ligand can be the key-step of the isomerization. The limits of a reaction that allows to prepare several yet-unknown products is discussed.