Facile Chemo-, Regio-, and Diastereoselective Approach to <i>cis</i>-3,5-Disubstituted γ-Butyrolactones and Fused γ-Butyrolactones
作者:Md. Merajuddin Baag、Vedavati G. Puranik、Narshinha P. Argade
DOI:10.1021/jo0619128
日期:2007.2.1
Chemoselective SN2‘ condensation of primary enolates of alkyl methyl ketones 2a−e with dimethyl bromomethylfumarate (1) followed by highly diastereoselective NaBH4 reduction of the ketone function in the formed ketodiesters 3a−e and the regioselective in situ lactonization of the unisolable intermediates 4a−e exclusively furnished the cis-3,5-disubstituted γ-butyrolactones (±)-5a−e in very good yields
化学选择性小号Ñ 2'烷基甲基酮的初级烯醇化物的缩合2A - ë用二甲bromomethylfumarate(1后跟高度非对映选择性的NaBH)4中所形成的ketodiesters还原酮功能的图3a - Ë并在unisolable中间体的原位内酯化的区域选择性图4a - Ë专门布置的顺式-3,5-二取代的γ丁内酯(±) - 5A - ë中非常良好的产率。同样,环己酮烯酸酯与1的面选择性偶联反应形成比例为8:2的非对映异构体的混合物,然后对9加10进行高度选择性的还原环化,仅以70%的总收率提供了顺式-八氢苯并呋喃(±)-12。