bidentate P-alkene ligands was observed in the presence of Lewis basic solvents, and model compounds of mono- and bis-solvated species (13, 14) were isolated. Cu formed trigonal-planar neutral (15−17) and cationic complexes (18, 19) of the general formulas [CuI(κ1P-alkene)2] and [Cu(κ1P-alkene)2BF4], respectively (P-alkene = 2, 4, 5). The cationic Rh species 11 catalyzed the 1,4-addition of arylboronic
Palladium-Catalyzed Enantioselective Conjugate Addition of Arylboronic Acids
作者:Francesca Gini、Bart Hessen、Adriaan J. Minnaard
DOI:10.1021/ol052222d
日期:2005.11.1
[reaction: see text] The first asymmetric palladium-catalyzed conjugate addition of arylboronic acids to alpha,beta-unsaturated aldehydes, ketones, and esters is described. For cyclic substrates, excellent chemo-, regio-, and enantioselectivities are achieved when a Pd(O2CCF3)2/DuPHOS catalyst is applied.
Functionalized N-Heterocyclic Carbene Ligands for Dual Enantioselective Control in the Cu-Catalyzed Conjugate Addition of Dialkylzinc Compounds to Acyclic Enones
A series of highly tunable, functionalized azolium compounds have been synthesized from chiral α-amino acid derivatives such as β-amino alcohols or α-amino esters. The combination of a Cu salt and a chiral azolium efficiently facilitated the asymmetric conjugate addition (ACA) reactions of acyclic enones with dialkylzinc under ambient conditions without temperature control. Of the (hydroxy amide)-functionalized
Conjugate additions of Gilman cyanocuprates to (S)‐N‐amino‐2‐(methoxymethyl)pyrrolidine (SAMP)‐hydrazones 4, 5 derived from cyclic and acyclic α,β‐unsaturated ketones were investigated. A protocol utilizing copper(II) sulfate/ammonium chloride was evolved, which allowed cleavage of SAMP (S)‐1 under the hydrolysis and work‐up conditions, followed by recovery of the auxiliary with ethylenediaminetetraacetic