Palladium(II) mediated aziridination of olefins with bromamine-T as the nitrogen source: scope and mechanism
摘要:
The palladium(II)-promoted reaction of a variety of olefins and bromamine-T provided N-tosyl-2-substituted aziridines under mild conditions. Olefins bearing chiral appendages gave only a poor to modest diastereoselectivity. Appropriate deuterated olefins were selected to study the stereochemistry of the reaction. A Pd(IV) intermediate is proposed as the aziridinating species. (C) 2007 Elsevier Ltd. All rights reserved.
Ruthenium-catalyzed, site-selective C–H activation: access to C5-substituted azaflavanone
作者:Manickam Bakthadoss、Tadiparthi Thirupathi Reddy、Duddu S. Sharada
DOI:10.1039/d0ra06580c
日期:——
A site-selective ruthenium-catalyzed keto group assisted C–H bond activation of 2-aryl tetrahydroquinoline (azaflavanone) derivatives has been achieved with a variety of alkenes for the first time. A wide range of substrates was utilized for the synthesis of a wide variety of alkenylated azaflavanones. This simple and efficient protocol provides the C5-substituted azaflavanone derivatives in high yields
The alkaloids (+)- and (−)-indolizidine 167B were synthesized via radicaladdition of a carbon radical to a chiral acrylamide. Further cyclization in the presence of BBr3, treatment with ‘nickel boride’ and stereospecifichydrogenation over palladium/carbon in acetic acid were other key steps in this synthesis.
In this protocol, an efficient palladium-catalyzed asymmetric synthesis of axially chiral conjugated dienes via alkenyl C–H olefination is reported. The corresponding atropisomeric styrenes containing a conjugated diene scaffold were obtained in good yields with good enantioselectivities. This synthetic strategy features an easy operation, mild reaction conditions, a wide functionality tolerance, and
A protocol for the synthesis of C5-olefinated 2-arylchromanones in a regio- and stereoselective fashion through the ruthenium-catalyzed oxidative coupling of diversified 2-arylchromanones with various alkenes through a keto-directed, site-selective C–Hactivation reaction is developed. IBO = isobornyl.