An efficient approach for the synthesis of 2,2-disubstituted indolin-3-ones is described. From readily accessible aryl hydrazines and allyloxyketones, 2,2-disubstituted indolin-3-ones could be obtained in good to excellent yields under mild reaction conditions via cascade Fischer indolization/Claisen rearrangement process. This protocol provides a facile entry to 2,2-disubstituted indolin-3-ones, which
Rhodium-Catalyzed Asymmetric Tandem Cyclization for Efficient and Rapid Access to Underexplored Heterocyclic Tertiary Allylic Alcohols Containing a Tetrasubstituted Olefin
作者:Yi Li、Ming-Hua Xu
DOI:10.1021/ol500993h
日期:2014.5.16
Rh-catalyzed asymmetric tandem cyclization of nitrogen- or oxygen-bridged 5-alkynones with arylboronic acids was achieved. The simple catalytic system involving a rhodium(I) complex with readily available chiral BINAP ligand promotes the reaction to proceed in a highly stereocontrolled manner. This protocol provides a very reliable and practical access to a variety of chiral heterocyclic tertiary allylic
presence of a catalytic amount of rhodium(I) complex having a diolefin ligand to afford 2-alkylidenecyclopentanols through the regioselective addition of an arylrhodium(I) species across the carbon-carbontriple bond, followed by intramolecular nucleophilic addition of the resulting vinylrhodium(I) species to the carbonyl group.
Precatalyst‐Enabled Selectivity: Enantioselective NiH‐Catalyzed
<i>anti</i>
‐Hydrometalative Cyclization of Alkynones to
<i>Endo</i>
‐ and Heterocyclic Allylic Alcohols
作者:Xiao‐Wen Zhang、Ming‐Hui Zhu、Hai‐Xiang Zeng、Qi‐Yang Li、Wen‐Bo Liu
DOI:10.1002/anie.202110815
日期:2021.12.20
AbstractA highly enantioselective NiH‐catalyzed hydrocyclization of alkynones with unparalleled anti‐ and endocyclic selectivities is described. The choice of the precatalysts has significant influence in tuning the regio‐ and enantioselectivity. Using Ni(OTs)2/Phox as a precatalyst and (EtO)2MeSiH as a hydride source, an array of enantioenriched O‐, N‐, and S‐containing heterocyclic tertiary allylic alcohols are obtained in 24–81 % yields with 80:20–99:1 er. Mechanistic investigations and synthetic application are also carried out. This study represents an efficient access to a set of allylic alcohols that are unable to access by the state‐of‐the‐art coupling reactions.
Rhodium-catalyzed arylative cyclization of alkynones induced by addition of arylboronic acids
Alkynones react with arylboronic acids in the presence of a rhodium(I) catalyst to afford four- and five-membered-ring cyclic alcohols equipped with a tetrasubstituted exocyclic olefin. The cyclic allylic alcohol skeleton is constructed by the carbon-carbon bond formation between the carbonyl group and an alkenylrhodium(I) intermediate formed by the regioselective addition of an arylrhodium(I) species across the carbon-carbon triple bond. (c) 2007 Elsevier Ltd. All rights reserved.