title: Zinc-catalyzed allenylations of aldehydes and ketones.
abstract: The general zinc-catalyzed allenylation of aldehydes and ketones with an allenyl boronate is presented. Preliminary mechanistic studies support a kinetically controlled process wherein, after a site-selective B/Zn exchange to generate a propargyl zinc intermediate, the addition to the electrophile effectively competes with propargyl-allenyl zinc equilibration. The utility of the methodology was demonstrated by application to a rhodium-catalyzed [4+2] cycloaddition.
authors.affiliation: Chemical Development, Boehringer-Ingelheim Pharmaceuticals Inc., 900 Ridgebury Road, P.O. BOX 368, Ridgefield, Connecticut 06877-0368, USA. daniel.fandrick@boehringer-ingelheim.com
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Fandrick
authors.forename: Jaideep
authors.initials: J
authors.lastname: Saha
authors.forename: Keith R
authors.initials: KR
authors.lastname: Fandrick
authors.forename: Sanjit
authors.initials: S
authors.lastname: Sanyal
authors.forename: Junichi
authors.initials: J
authors.lastname: Ogikubo
authors.forename: Heewon
authors.initials: H
authors.lastname: Lee
authors.forename: Frank
authors.initials: F
authors.lastname: Roschangar
authors.forename: Jinhua J
authors.initials: JJ
authors.lastname: Song
authors.forename: Chris H
authors.initials: CH
authors.lastname: Senanayake
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000466:Alkadienes / Q000138:chemical synthesis* / Q000737:chemistry; D001896:Boron Compounds / Q000737:chemistry*; D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D003500:Cyclization; D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D012238:Rhodium / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D000447:Aldehydes; D000466:Alkadienes; D001896:Boron Compounds; D007659:Ketones; C025947:propadiene; D012238:Rhodium; D015032:Zinc