一种简便的化学、区域和非对映选择性合成顺式-3,5-二取代γ-丁内酯和稠合γ-丁内酯的方法。

Facile chemo-, regio-, and diastereoselective approach to cis-3,5-disubstituted gamma-butyrolactones and fused gamma-butyrolactones.

作者信息

Baag Md Merajuddin, Puranik Vedavati G, Argade Narshinha P

机构信息

Division of Organic Chemistry (Synthesis) and Centre for Material Characterization, National Chemical Laboratory, Pune 411 008, India.

出版信息

J Org Chem. 2007 Feb 2;72(3):1009-12. doi: 10.1021/jo0619128.

DOI:10.1021/jo0619128

PMID:17253824

Abstract

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 gamma-butyrolactones (+/-)-5a-e in very good yields. Similarly, the face-selective coupling reaction of cyclohexanone enolate with 1 to form a mixture of diastereomers in an 8:2 ratio followed by a highly selective reductive cyclization of 9 plus 10 exclusively provided the cis-octahydrobenzofuran (+/-)-12 in 70% overall yield.

摘要

烷基甲基酮2a - e的伯烯醇盐与溴甲基富马酸二甲酯(1)进行化学选择性SN2'缩合反应，随后对生成的酮二酯3a - e中的酮官能团进行高非对映选择性NaBH4还原，以及对不可分离的中间体4a - e进行区域选择性原位内酯化反应，以非常高的产率专一性地得到了顺式-3,5-二取代γ-丁内酯(±)-5a - e。同样，环己酮烯醇盐与1进行面选择性偶联反应，以8:2的比例形成非对映异构体混合物，随后9和10进行高选择性还原环化反应，以70%的总产率专一性地得到了顺式八氢苯并呋喃(±)-12。