Metal-Free Carbonyl-Assisted Regioselective Hydration of Alkynes: An Access to Dicarbonyls
作者:Shalini Verma、Manoj Kumar、Pawan K. Mishra、Akhilesh K. Verma
DOI:10.1021/acs.orglett.9b01649
日期:2019.7.5
Metal-free regioselective hydration of o-alkynylaldehydes with the assistance of neighboring carbonyl oxygen is disclosed. The developed protocol provides a facile route to synthesize a series of multisubstituted carbonyl containing scaffolds that enable the potential application toward the synthesis of highly diversified 5-azaindoles. gamma-Carbolines and 2,8-diazacarbazoles can also be accessed directly without isolating the dicarbonyl compounds. The developed methodology is operationally simple and environment-friendly, tolerates a wide variety of functional groups, and is applicable toward large scale synthesis.
Synthesis of β- and γ-Carbolines by the Palladium/Copper-Catalyzed Coupling and Cyclization of Terminal Acetylenes
作者:Haiming Zhang、Richard C. Larock
DOI:10.1021/jo0258857
日期:2002.10.1
A variety of 3-substituted beta- and gamma-carbolines have been synthesized from N-substituted 3-iodoindole-2-carboxaldehydes and 2-bromoindole-3-carboxaldehydes, respectively. The coupling of these aldehydes with various terminal acetylenes with PdCl2(PPh3)(2)/CuI as the catalyst readily affords the corresponding alkynylindole carboxaldehydes, which have subsequently been converted to the corresponding tert-butylimines and cyclized to beta- and gamma-carbolines by either copper-catalyzed or thermal processes.
Deprotection of N-sulfonyl nitrogen-heteroaromatics with tetrabutylammonium fluoride
作者:Akito Yasuhara、Takao Sakamoto
DOI:10.1016/s0040-4039(97)10653-0
日期:1998.2
The deprotection of N-methylsulfonyl, N-(p-toluenesufonyl), and N-phenylsulfonyl nitrogen-heteroaromatic compounds proceeds easily in excellent yields by refluxing with tetrabutylammonium fluoride (TBAF) in THF. (C) 1998 Elsevier Science Ltd. All rights reserved.