Acceleration of hetero-Michael reaction by symmetrical pentacyclic guanidines
摘要:
Symmetrical pentacyclic guanidines 1a-c and 2 which contain the core skeleton of 13,14,15-isocrmbescidine 800, have been synthesized. In the presence of catalytic amounts of these guanidines 1, the reaction rate of the conjugate addition of pyrrolidine (9) to gamma -crotonolactone (10) could be enhanced depending upon the size of the cavities and substituents on tetrahydropyran rings of 1 and 2. (C) 2001 Elsevier Science Ltd. All rights reserved.
Dihydroxydibutylether (DHBE) is a cholereticdrug used for the treatment of gallstone and hepatic disorders due to its choleretic activity and hepatoprotective action. The drug is a mixture of three regioisomers. The main regioisomer 3‐(3‐hydroxylbutoxy)‐1‐butanol (III) contains four stereoisomers, including (R)‐3‐((R)‐3‐hydroxylbutoxy)‐1‐butanol (IIIa), (R)‐3‐((S)‐3‐hydroxylbutoxy)‐1‐butanol (IIIb)
Stereoselective synthesis of resorcylic acid lactone Cochliomycin B
作者:G. Nagalatha、N. Siva Ganesh、A. Venkat Narsaiah
DOI:10.1016/j.tetlet.2021.153410
日期:2021.10
The total synthesis of 14-membered resorcylic acidlactone, Cochliomycin B has prescribed, in a convergent manner, from readily available starting materials, d-galactose, l-aspartic acid and ethyl acetoacetate. The key reactions involved in the synthesis are Julia-Kocienski olefination, E-selective Horner-Wadsworth-Emmons olefination and intramolecular lactonization.
14 元间苯二甲酸内酯的全合成,Cochliomycin B 以收敛的方式规定,从容易获得的起始原料,d-半乳糖,l-天冬氨酸和乙酰乙酸乙酯。合成中涉及的关键反应是 Julia-Kocienski 烯化、E-选择性 Horner-Wadsworth-Emmons 烯化和分子内内酯化。