Diastereoselective nickel-catalyzed reductive aldol cyclizations using diethylzinc as the stoichiometric reductant: scope and mechanistic insight.
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.
Joensuu
Pekka M
PM
School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings, West Mains Road, Edinburgh, EH9 3JJ, United Kingdom.
Murray
Gordon J
GJ
Fordyce
Euan A F
EA
Luebbers
Thomas
T
Lam
Hon Wai
HW
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
D000085:Acetates; D000475:Alkenes; D000577:Amides; D004952:Esters; D007659:Ketones; D007769:Lactams; D007783:Lactones; D009942:Organometallic Compounds; C119536:nickel acetate; C454811:diethylzinc