Sulfoxides as Stereochemical Controllers in Intermolecular Heck Reactions
摘要:
The study of a variety of substituted sulfoxides as chiral auxiliaries in intermolecular Heck reactions of sulfinyldihydrofurans and sulfinylcyclopentenes with different iodoarenes is reported. In the presence of [Pd(OAc)(2)]/Ag2CO3 and a bidentate phosphine ligand, synthetically useful yields and asymmetric inductions were obtained. By far the best diastereoselectivities were obtained by the use of the palladium-coordinating o-(N,N-dimethylamino)phenylsulfinyl group. By final removal of the chiral auxiliary, these sulfoxide-stereocontrolled asymmetric Heck processes were applied to the enantioselective synthesis of 1-aryl-substituted and 1,3-diaryl-substituted dihydrofurans and cyclopentenes.
Chiral P,N-Ligands Based on Ketopinic Acid in the Asymmetric Heck Reaction
作者:Scott R. Gilbertson、Zice Fu
DOI:10.1021/ol006747b
日期:2001.1.1
[figure: see text] Novel chiral P,N-ligands were synthesized from (1S)-(+)-ketopinic acid using palladium-catalyzedcouplingreaction of a vinyl triflate and either a diarylphosphine or a dialkylphosphine as the key step. Palladium complexes of these ligands are efficient catalysts for asymmetric Heck reaction between aryl or alkenyl triflates and cyclic alkenes. Products were obtained with good to
Rational design of cyclopropane-based chiral PHOX ligands for intermolecular asymmetric Heck reaction
作者:Marina Rubina、William M Sherrill、Alexey Yu Barkov、Michael Rubin
DOI:10.3762/bjoc.10.158
日期:——
rigid cyclopropyl backbone was synthesized and tested in the intermolecularasymmetricHeck reaction. Mechanistic modelling and crystallographic studies were used to predict the optimal ligand structure and helped to design a very efficient and highly selective catalytic system. Employment of the optimized ligands in the asymmetricarylation of cyclic olefins allowed for achieving high enantioselectivities
BINAP versus BINAP(O) in Asymmetric Intermolecular Mizoroki-Heck Reactions: Substantial Effects on Selectivities
作者:Thorsten H. Wöste、Martin Oestreich
DOI:10.1002/chem.201101695
日期:2011.10.10
2′‐Bis(diphenylphosphino)‐1,1′‐binaphthyl (BINAP) was employed as chiral ligand in the enantioselective intermolecularMizoroki–Heckreaction, whereas the use of cognate BINAP(O) (monooxidized BINAP) is unprecedented. The regio‐ and enantioselectivity of the arylation of representative cyclic alkenes changes dramatically in the presence of hemilabile BINAP(O) instead of BINAP. The arylation of 2,3‐dihydrofuran
Tandem Copper-Catalyzed Enantioselective Allylation−Metathesis
作者:Alexandre Alexakis、Karine Croset
DOI:10.1021/ol0269244
日期:2002.11.1
Grignardreagents undergo enantioselective (up to 86% ee) copper-catalyzed S(N)2' substitution on achiral allylic chlorides. The reaction is wide in scope for both the Grignardreagent and the allylic substrate. The resulting terminal alkene could be submitted to intra- or intermolecular metathesis to afford newchiral synthons. The experimental conditions are compatible with a one-pot overall sub
zine ligands 2 were applied in asymmetric catalysis. Rhodium and copper complexes catalyzed the hydrosilylation of acetophenone and [4+2] cycloadditions with moderate enantioselectivity. Iridium complexes were used to hyrogenate di-, tri-, and tetrasubstituted alkenes, giving products with moderate to high enantiomer excesses. Enantioselective allylic substitution and Heckreactionscatalyzed by [