Chiral P,N-Ligands Based on Ketopinic Acid in the Asymmetric Heck Reaction

Abstract

[figure: see text] Novel chiral P,N-ligands were synthesized from (1S)-(+)-ketopinic acid using palladium-catalyzed coupling reaction 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 excellent enantioselectivity from arylation and alkenylation of 1,2-dihydrofuran, cyclopentene, and 4,7-dihydro-1,3-dioxepin.

The Synthesis of New HetPHOX Ligands and Their Application to the Intermolecular Asymmetric Heck Reaction

“…The results of the base screen, Table 1, show that good to excellent conversions and excellent enantioselectivities were achieved in all cases for this initial study. As is consistent with many P,N ligands [9][10][11][12][13] low amounts of the thermodynamic product 11 were observed.…”

“…The groups of Guiry, [9] Gilbertson, [10] Hashimoto, [11] and Hou [12] have all developed highly selective P,N systems with varying chiral scaffolds. [13] Our more [a] Centre for Synthesis and Chemical Biology, School of Chemistry and Chemical Biology, UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland Supporting information for this article is available on the WWW under http://www.eurjoc.org or from the author.…”

The Development of Bidentate P,N Ligands for Asymmetric Catalysis

“…These have been applied in the intermolecular Heck reaction where 300 gave excellent enantioselection with a number of substrates, Scheme 22. [109] This selectivity for the kinetic regiosomer, in which the double bond stays where it was originally formed, without subsequent isomerisation, was previously noted for the phosphinooxazolines 259 ± 263.…”

Palladium Nanoparticles in Allylic Alkylations and Heck Reactions: The Molecular Nature of the Catalyst Studied in a Membrane Reactor

“…Conversion and selectivity were determined by GC. [36] Procedure for Heck Reaction using Palladium Molecular Systems À2 mmol) and the corresponding chiral ligand (2. 8 10 À2 mmol) in dry degassed THF (3.0 mL) was stirred under argon at room temperature for 15 min.…”