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
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
复制标题
DOI：
10.1016/s0040-4039(02)01128-0
复制
发表时间：
2002-08-05
影响因子：
1.8
通讯作者：
Negishi, E
中科院分区：
文献类型：
--
作者：
Anastasia, L;Xu, C;Negishi, E
用 5·10 mol% ZnBr2 处理通过 Pd 催化的炔基锌-β-卤代丙烯酸偶联制备的 (Z)-5-烷基-2-en-4-炔酸 (1) 可生成 6-烷基-2H-吡喃-2-酮 (2) 以及少量 (Z)-5-亚烷基呋喃-2(5H) 酮 (3)，总含量 >90%产率通常非常高（大约 95/5）吡喃酮/呋喃酮比率。另一方面，Ag2CO3 催化的 1 内酯化提供了 (Z)-5-亚烷基呋喃-2(5H)-酮 (3) 的选择性合成，产率 >90% 以及少量（小于或等于 5%）的 2。 (C) 2002 由 Elsevier Science Ltd 出版。
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.