title: A new type of catalytic tandem 1,4-addition-aldol reaction which proceeds through an (oxa-pi-allyl)rhodium intermediate.
abstract: The reaction of 9-aryl-9-borabicyclo[3.3.1]nonanes (B-Ar-9BBN) with alpha,beta-unsaturated ketones and aldehydes in the presence of 3 mol % [Rh(OMe)(cod)](2) in toluene at 20 degrees C for 2 h gave high yields of the tandem 1,4-addition-aldol reaction products with high syn selectivity. The reaction proceeds through the catalytic cycle consisting of 1,4-addition of an organorhodium species to an alpha,beta-unsaturated ketone and the aldol addition of the resulting (oxa-pi-allyl)rhodium intermediate to an aldehyde.
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo, Kyoto 606-8502, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yoshida
authors.forename: Masamichi
authors.initials: M
authors.lastname: Ogasawara
authors.forename: Tamio
authors.initials: T
authors.lastname: Hayashi