title: Vitamin B12S-promoted model rearrangement of methylmalonate to succinate is not a free radical reaction.
abstract: To probe for free radical intermediates in the model methylmalonate to succinate rearrangements promoted by vitamin B12s, a model series with a pentenyl side chain radical trap has been devised. The control free radical, generated by tri-n-butyltin hydride treatment of bromomethyl-pentenylmalonate thioester, undergoes rapid cyclization to the six-membered ring, and, as anticipated, no succinate rearrangement product is detected. By contrast when the bromide is treated with vitamin B12s, little cyclized product is observed; the major product is the pentenyl succinate. This result demonstrates that the latter rearrangement does not follow a free radical pathway.
authors.affiliation: Department of Chemistry, University of Pittsburgh, PA 15260.
authors.forename: G Y
authors.initials: GY
authors.lastname: Choi
authors.forename: S C
authors.initials: SC
authors.lastname: Choi
authors.forename: A
authors.initials: A
authors.lastname: Galan
authors.forename: B
authors.initials: B
authors.lastname: Wilk
authors.forename: P
authors.initials: P
authors.lastname: Dowd
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D005609:Free Radicals; D008314:Malonates; D013386:Succinates; D019802:Succinic Acid; D014805:Vitamin B 12
chemical_list: D005609:Free Radicals; D008314:Malonates; D013386:Succinates; D019802:Succinic Acid; C005230:methyl malonate; D014805:Vitamin B 12