6-PI-ELECTROCYCLIZATION OF 1-AZATRIENES TO 1,2-DIHYDROPYRIDINES

被引：98

作者：

MAYNARD, DF ^{[1
]}

OKAMURA, WH ^{[1
]}

机构：

[1] UNIV CALIF RIVERSIDE,DEPT CHEM,RIVERSIDE,CA 92521

来源：

JOURNAL OF ORGANIC CHEMISTRY | 1995年 / 60卷 / 06期

关键词：

D O I：

10.1021/jo00111a039

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

A series of alpha,beta-cis-dienals were synthesized by oxidation and then in situ isomerization of easily available beta-allenic alcohols. Subsequent reaction between the alpha,beta-cis-dienals and primary amines represents a simple and useful method for the direct preparation of 1,2-dihydropyridines. Reactivity profiles and activation parameters for the cyclization of alpha,beta-cis-dienimines are similar to those of the carbocyclic counterparts except the reaction is much faster. Despite the lack of a clear stereochemical label, the disrotatory nature of the ring closure is illustrated by the greater cyclization rates of 8'c and 8'd as compared to 7'c and 7'd, respectively. The observation that sterically more hindered systems (8'c and 8'd) cyclize faster than less hindered ones (7'c and 7'd) is a feature of 6 pi-electrocyclizations that is unprecedented.

引用

页码：1763 / 1771

页数：9

共 45 条

[1] REACTION OF COPPER ENOLATES OF ESTERS WITH PROPARGYLIC SYSTEMS - FACILE PREPARATION OF 3,4-DIENOIC ESTERS, STEREOSELECTIVE REARRANGEMENT TO (2E,4Z)-DIENOIC AND (2E,4E)-DIENOIC ESTERS, AND STEREOSELECTIVE SYNTHESIS OF A FRAGRANCE FROM BARTLETT PEAR [J].