Silver-catalyzed cyclopropanation of alkenes with alkynyl <i>N</i>-nosylhydrazones leading to alkynyl cyclopropanes
作者:Yongquan Ning、Mengtian Huo、Lizuo Wu、Xihe Bi
DOI:10.1039/d2cc00099g
日期:——
Here, a novel method for the stereoselective synthesis of alkynyl cyclopropanes, by the silver-catalyzed alkynylcyclopropanation of alkenes using alkynyl N-nosylhydrazones as alkynyl carbene precursors, is reported.
5-Hydroxyindoles by Intramolecular Alkynol–Furan Diels–Alder Cycloaddition
作者:Matthew LaPorte、Ki Bum Hong、Jie Xu、Peter Wipf
DOI:10.1021/jo3022605
日期:2013.1.4
A convergent approach provides a convenient access to synthetically and biologically useful 3,4-disubstituted 5-hydroxyindoles. The one-pot procedure uses microwave heating to initiate an intramolecular [4 + 2]-cycloaddition of an alkynol segment onto a furan followed by a fragmentation, aromatization, and N-Boc deprotection cascade. Yields range from 15 to 74%, with aromatic substituents providing better conversions. 4-Trimethylsilylated analogues undergo a 1,3-silatropic rearrangement to give the O-TMS ethers.