Catalytic and selective conversion of (Z)-2-en-4-ynoic acids to either 2H-pyran-2-ones in the presence of ZnBr2 or (Z)-5-alkylidenefuran-2(5H)-ones in the presence of Ag2CO3

被引:88
作者
Anastasia, L [1 ]
Xu, C [1 ]
Negishi, E [1 ]
机构
[1] Purdue Univ, Herbert C Brown Labs, W Lafayette, IN 47907 USA
基金
美国国家卫生研究院; 美国国家科学基金会;
关键词
D O I
10.1016/S0040-4039(02)01128-0
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Treatment of (Z)-5-alkyl-2-en-4-ynoic acids (1), prepared by the Pd-catalyzed alkynylzinc-beta-haloacrylic acid coupling, with 5 10 mol% of ZnBr2 can produce 6-alkyl-2H-pyran-2-ones (2) along with minor amounts of (Z)-5-alkylidenefuran-2(5H)ones (3) in >90% combined yields, with often very high (approximate to95/5) pyranone/furanone ratios. On the other hand, lactonization of 1 catalyzed by Ag2CO3 provides a selective synthesis of (Z)-5-alkylidenefuran-2(5H)-ones (3) in >90% yields along with minor amounts (less than or equal to5%) of 2. (C) 2002 Published by Elsevier Science Ltd.
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页码:5673 / 5676
页数:4
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