We report an electrophile promoted, highly regioselective (∼100%) synthesis of 5-membered haloimidiates from 2-(1-alkynyl)benzamides under metal free conditions. The steric bulk in association with neighbouring group assistance at the propargylic carbon of an alkyne has been employed as the dictating factor to achieve the regioselectivity. A very broad structural diversity has been observed for propargylic
The selective synthesis of (Z)‐ or (E)‐3‐aryl/vinyl/alkylidene‐isoindolones, and 2‐benzopyran derivatives from o‐(1‐alkynyl)benzamides by means of a suitable choice of bases or silver catalysis is described.
A Highly Regio and Stereoselective Synthesis of (<i>Z</i>)-3-Aryl(alkyl)idene Isoindolin-1-ones via Palladium Catalyzed Annulation of Terminal Alkynes
作者:M. Khan、Nitya Kundu
DOI:10.1055/s-1997-1049
日期:——
o-Iodobenzamide or its N-substituted derivatives 4-10 and terminal alkynes 11-17 reacted in DMF in the presence of bis(triphenylphosphine)palladium(II)chloride, cuprous iodide and triethylamine leading to (Z)-3-arylidene isoindolin-1-ones (22, 24, 27 and 28) or o-alkynyl N-substituted benzamides (I). The latter could be cyclised with sodium in ethanol in a completely regio and stereoselective manner to (Z)-3-aryl(alkyl)idene isoindolin-1-ones 18-35.
Palladium-Catalysed Heteroannulation with Terminal Alkynes: a Highly Regio- and Stereoselective Synthesis of (Z)-3-Aryl(alkyl)idene Isoindolin-1-ones
作者:Nitya G Kundu、M.Wahab Khan
DOI:10.1016/s0040-4020(00)00359-8
日期:2000.6
A highly regio- and stereoselective method for the synthesis of (Z)-3-aryl(alkyl)idene isoindolin-1-ones through palladium-copper catalysis is described. 2-Iodobenzamide 1 and its substituted derivatives 2-10 were reacted with terminal alkynes 11-19 in the presence of (PPh3)(2)PdCl2, CuI, and Et3N in DMF mostly at 80 degrees C for 16 h to yield the 2-alkynyl substituted benzamides 20-38, 40-45, 77 which could then be cyclised with NaOEt in EtOH to the 3-aryl(alkyl)idene isoindolin-1-ones 46-49, 51, 53-55, 57, 59-71, 73 and 75. In certain cases, the isoindolin-1-ones 50, 52, 56 and 58 could be directly obtained by the palladium-catalysed reactions. (C) 2000 Elsevier Science Ltd. All rights reserved.