title: Diastereoselective nickel-catalyzed reductive aldol cyclizations using diethylzinc as the stoichiometric reductant: scope and mechanistic insight.
abstract: In the presence of diethylzinc as a stoichiometric reductant, Ni(acac) 2 functions as an efficient precatalyst for the reductive aldol cyclization of alpha,beta-unsaturated carbonyl compounds tethered to a ketone electrophile through an amide or an ester linkage. The reactions are tolerant of a wide range of substitution at both alpha,beta-unsaturated carbonyl and ketone components and proceed smoothly to furnish beta-hydroxylactams and beta-hydroxylactones with generally high diastereoselectivities. A series of experiments, including deuterium-labeling studies, was carried out in an attempt to gain some insight into the possible reaction mechanisms that might be operative.
authors.affiliation: School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings, West Mains Road, Edinburgh, EH9 3JJ, United Kingdom.
authors.forename: Pekka M
authors.initials: PM
authors.lastname: Joensuu
authors.forename: Gordon J
authors.initials: GJ
authors.lastname: Murray
authors.forename: Euan A F
authors.initials: EA
authors.lastname: Fordyce
authors.forename: Thomas
authors.initials: T
authors.lastname: Luebbers
authors.forename: Hon Wai
authors.initials: HW
authors.lastname: Lam
mesh_terms: D000085:Acetates / Q000737:chemistry*; D000475:Alkenes / Q000737:chemistry; D000577:Amides / Q000737:chemistry; D003500:Cyclization; D004952:Esters / Q000737:chemistry; D007659:Ketones / Q000737:chemistry; D007769:Lactams / Q000138:chemical synthesis*; D007783:Lactones / Q000138:chemical synthesis*; D009942:Organometallic Compounds / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000085:Acetates; D000475:Alkenes; D000577:Amides; D004952:Esters; D007659:Ketones; D007769:Lactams; D007783:Lactones; D009942:Organometallic Compounds; C119536:nickel acetate; C454811:diethylzinc