Enantioselective conversion of primary alcohols to α-exo-methylene γ-butyrolactones via iridium-catalyzed C-C bond-forming transfer hydrogenation: 2-(alkoxycarbonyl)allylation.
Upon exposure of acrylic ester 1 to alcohols 2a-i in the presence of a cyclometalated iridium catalyst modified by (-)-TMBTP, catalytic C-C coupling occurs, providing enantiomerically enriched 5-substituted α-exo-methylene γ-butyrolactones 3a-i. Bromination of the methylene butyrolactone products followed by zinc-mediated reductive aldehyde addition provides the disubstituted α-exo-methylene γ-butyrolactones 6a and 6b with good to excellent levels of diastereoselectivity.
Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712, USA.
T Patrick
TP
Montgomery
Abbas
A
Hassan
Boyoung Y
BY
Park
Michael J
MJ
Krische
D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D000438:Alcohols / Q000737:chemistry*; D000498:Allyl Compounds / Q000737:chemistry*; D002384:Catalysis; D006865:Hydrogenation; D007495:Iridium / Q000737:chemistry*; D013237:Stereoisomerism
D000438:Alcohols; D000498:Allyl Compounds; C014096:alpha-methylene gamma-butyrolactone; D007495:Iridium; D015107:4-Butyrolactone