An intramolecular 1,3-dipolar cycloaddition/electrophilic cyclization sequence to give cyclic ethers
摘要:
An intramolecular 1,3-dipolar cycloaddition/electrophilic cyclization sequence has been developed for the synthesis of cyclic ethers. This approach utilizes a diastereoselective nitrile oxide 1,3-dipolar cycloaddition to give furoisoxazoles, which undergo subsequent electrophilic cyclization to afford substituted tetrahydrofurans.
One-pot synthesis of five-membered cyclic thioethers or ethers via intramolecular nitrile oxide-olefin cycloaddition (INOC) or intramolecular alkoxycarbonyl nitronate-olefin cycloaddition (IAOC) by the use of methyl chloroformate
作者:Ming-Chung Yan、Jing-Yuan Liu、Wen-Wei Lin、Kuo-Hsi Kao、Ju-Tsung Liu、Jeong-Jiunn Jang、Ching-Fa Yao
DOI:10.1016/s0040-4020(99)00741-3
日期:1999.10
with allyl alcohol and base, can be converted into methoxycarbonyl nitronates 22 by treating the solution with methyl chloroformate and calytic amount of 4-dimethylaminopyridine (DMAP) in the presence of different amounts of triethylamine. Intermediates 22 can either undergo intramolecular alkoxycarbonyl nitronate-olefin cycloaddition (IAOC) to generate highly stereoselective product trans-14 or undergo
An intramolecular 1,3-dipolar cycloaddition/electrophilic cyclization sequence to give cyclic ethers
作者:Xenia Beebe、Cynthia L. Chiappari、Mark J. Kurth、Neil E. Schore
DOI:10.1021/jo00078a003
日期:1993.12
An intramolecular 1,3-dipolar cycloaddition/electrophilic cyclization sequence has been developed for the synthesis of cyclic ethers. This approach utilizes a diastereoselective nitrile oxide 1,3-dipolar cycloaddition to give furoisoxazoles, which undergo subsequent electrophilic cyclization to afford substituted tetrahydrofurans.
Lithium, potassium and sodium alkoxides: Donors in the Michael addition reaction of α-nitroolefins.
作者:Jetty L. Duffy、Jennifer A. Kurth、Mark J. Kurth
DOI:10.1016/s0040-4039(00)91768-4
日期:1993.2
Michael addition of potassio- or sodioalkoxides to α-nitroolefins provides essentially pure β nitroethers (1–10) in 78–100% isolated yield.