Syntheses and regiochemistry of enol addition to 9-phenyl-9H-xanthen-9-ol

被引：6

作者：

Kavala, Veerababurao ^{[1
]}

Murru, Siva ^{[1
]}

Das, Gopal ^{[1
]}

Patel, Bhisma K. ^{[1
]}

机构：

[1] Indian Inst Technol Guwahati, Dept Chem, Gauhati 781039, India

来源：

TETRAHEDRON | 2008年 / 64卷 / 18期

关键词：

D O I：

10.1016/j.tet.2008.02.053

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

Regioselective C-C bond formation of 9-phenyl-9H-xanthen-9-ol 1 with various enolizable ketones I-X in an acidic (HBr) medium, obtained by the reaction of 1, 1'-(ethane-1,2-diyl)dipyridinium bistribromide (EDPBT) with ketone is observed. Except for ketone, 4-methylpentan-2-one VII in all other cases examined the attack to xanthenyl carbocation is from the thermodynamically stable enolizable side of the unsymmetrical ketones. In the case of 3-methyl-butan-2-one VIII the equilibrium is in favor of the more stable enolizable ketone, which has large steric factor, hence no reaction was observed during its addition to alcohol 1. (c) 2008 Elsevier Ltd. All rights reserved.

引用

页码：3960 / 3965

页数：6

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