Control of Regioselectivity in Pd(0)-Catalyzed Coupling−Cyclization Reaction of 2-(2‘,3‘-Allenyl)malonates with Organic Halides
作者:Shengming Ma、Ning Jiao、Shimin Zhao、Hairong Hou
DOI:10.1021/jo0108616
日期:2002.5.1
in the Pd(0)-catalyzed coupling-cyclization of 2-(2',3'-allenyl)malonates with organichalides is determined by the steric and electronic effects of both substrates. By deliberate control of the reaction conditions, the regioselectivity of this reaction can be tuned. With conditions A and B, the reaction afforded vinylic cyclopropane derivatives, while with conditions C and D, the reaction afforded
Palladium-Catalyzed Highly Regio- and Stereoselective Addition of Organoboronic Acids to Allenes in the Presence of AcOH
作者:Shengming Ma、Ning Jiao、Longwu Ye
DOI:10.1002/chem.200305301
日期:2003.12.15
The Pd(0)-catalyzedregio- and stereoselective addition of organoboronicacids to allenes leads to stereodefined tri- or tetrasubstituted alkenes. Furthermore, this method shows high substitutent-loading capability and tolerance of various substitutents. A hydropalladation-Suzuki coupling mechanism, which may account for the regio- and stereoselectivity, is proposed.
new method for the synthesis of di‐ and trisubstituted pyrroles via copper‐catalyzed cyclization of ethyl allenoates with activated isocyanides has been developed. In contrast to related annulation reactions previously reported, this new process features a skeletal rearrangement in which the aryl sulfonyl moiety, which functions as the electron‐withdrawing group in the α‐carbon of the isocyanide, was
A strategy for the β‐selective conjugate addition of α‐fluoro‐β‐ketoamides to allenicesters has been developed via phosphine catalysis and demonstrated for a wide range of ketoamides and allenoate substrates.
Substrate-controlled, PBu<sub>3</sub>-catalyzed annulation of phenacylmalononitriles with allenoates enables tunable access to cyclopentenes
作者:Narendra Kumar Vaishanv、Sanoop P Chandrasekharan、Mohd Khalid Zaheer、Ruchir Kant、Kishor Mohanan
DOI:10.1039/d0cc04688d
日期:——
phenacylmalononitriles with allenoates, controlled by the γ-substitution on allenoates, offers a tunable synthesis of multifunctionalized cyclopentene carboxamides and cyclopentenols. An unprecedented formation of cyclopentene carboxamide was observed when allenic esters bearing a substitution at the γ-position were employed, while unsubstituted allenoates produced cyclopentenols. The former reaction likely involves