Ammonia-Promoted Fragmentation of 2-Alkyl- and 2,4-Dialkyl-3-iodo-1- oxocyclohexan-2,4-carbolactones
摘要:
2-Alkyl- and 2,4-dialkyl-3-iodo-1-oxocyclohexan-2,4-carbolactones undergo ammonia-promoted fragmentation reactions to provide butenolides, gamma-butyrolactone, and/or, beta,gamma-epoxycyclohexanones. Product distribution is governed by the relative size of the substituents at C-2 and C-4 of the cyclohexanones. Butenolide amide, the major product from the fragmentation, is further converted into their respective piperidinone and pyrrolidine derivatives.
Asymmetric synthesis and fragmentation reactions of 2-alkyl- and 2, 4-dialkyl-3-iodo-1-oxocyclohexan-2, 4-carbolactones. Single enantiomer preparation of Δα, β-butenolides, 2-alkyl-4-hydroxy-2-cyclohexen-1-ones and butyrolactones
作者:Arthur G. Schultz、Mingshi Dai、Seock-Kyu Khim、Liping Pettus、Kshitij Thakkar
DOI:10.1016/s0040-4039(98)00785-0
日期:1998.6
Fragmentation reactions of keto iodolactones 4 provide access to butenolides 5, 2-alkyl-4-hydroxy-2-cyclohexen-1-ones 6, and butyrolactones 9. Delta(alpha,beta)-Butenolides 5e and 5f were converted to heterocycles 14-16 by way of intramolecular cycloaddition reactions. (C) 1998 Elsevier Science Ltd. All rights reserved.
Stereoselective dihydroxylation of 2-alkyl- and 2,4-dialkyl-2-amido-3-cyclohexen-1-ones. Synthesis of enantiomerically related 2-alkyl- and 2,4-dialkyl-3-hydroxy-1- oxocyclohexan-2,4-carbolactones by complementary buturolactonization reactions
作者:Arthur G. Schultz、Mingshi Dai、Fook S. Tham、Xuqing Zhang
DOI:10.1016/s0040-4039(98)01440-3
日期:1998.9
Stereoselective dihydroxylation of 2a-2f gives <(cis)under bar>-diols 3a-3f, from which hydroxylactones 5a-5f are obtained by an acid-catalyzed process involving retro aldol-realdolization prior to transesterification. (C) 1998 Elsevier Science Ltd. All rights reserved.