Cu(I)-Catalyzed Reductive Aldol Cyclizations:  Diastereo- and Enantioselective Synthesis of β-Hydroxylactones

Abstract

[reaction: see text] Copper bisphosphine complexes catalyze the intramolecular reductive aldol reaction of alpha,beta-unsaturated esters with ketones, affording five- and six-membered beta-hydroxylactones in high stereoselectivities. Utilization of chiral nonracemic bisphosphines render the cyclizations enantioselective.

Optimizing P,N‐Bidentate Ligands for Oxidative Gold Catalysis: Efficient Intermolecular Trapping of α‐Oxo Gold Carbenes by Carboxylic Acids

“…(3)]. [10] Another approach to cyclized products is shown in Equation (4), where DBU effectively promoted sequential intramolecular aldol reaction and dehy-dration of the ketones 3 ac and 3 ad, which in turn were obtained in excellent yields by the oxidative gold catalysis.…”

Domino Reactions Involving Catalytic Enantioselective Conjugate Additions

“…Recently, Lam reported on the first enantioselective intramolecular reductive domino conjugate addition/aldol reaction (Scheme 8.9) [18]. Reduction of the α,β-unsaturated ester 37 was performed using air-stable copper(II) acetate and tetramethyldisiloxane (TMDS) as the hydride source.…”

Catalytic Enantioselective Aldol Additions to Ketones

“…Lam and co-workers [34] used biphenylphosphane ligand 40/Cu(OAc) 2 catalyst system with tetramethylhydrosiloxane as a hydride source to achieve an intramolecular reductive aldol reaction of ketounsaturated esters 39 (Scheme 20). Lam and co-workers [34] used biphenylphosphane ligand 40/Cu(OAc) 2 catalyst system with tetramethylhydrosiloxane as a hydride source to achieve an intramolecular reductive aldol reaction of ketounsaturated esters 39 (Scheme 20).…”

“…Recently, asymmetric reductive aldol reaction of ketone was reported from three groups. Lam and co-workers [34] used biphenylphosphane ligand 40/Cu(OAc) 2 catalyst system with tetramethylhydrosiloxane as a hydride source to achieve an intramolecular reductive aldol reaction of ketounsaturated esters 39 (Scheme 20). The reaction provided β-hydroxylactones 41 diastereoselectively with moderate enantioselectivity.…”