title: Ti-crossed-Claisen condensation between carboxylic esters and acid chlorides or acids: a highly selective and general method for the preparation of various beta-keto esters.
abstract: Ti-crossed-Claisen condensation between a 1:1 mixture of carboxylic esters and acid chlorides promoted by TiCl4-Bu3N-N-methylimidazole proceeded successfully to give various beta-keto esters in good yields with excellent selectivities (19 examples, approximately 48-95% yield; cross/self-selectivity = approximately 96/4-99/1). The present method was extended to the condensation between a 1:1 mixture of carboxylic acids and carboxylic esters (six examples, approximately 70-92% yield; cross/self-selectivity = approximately 91/9-99/1). To demonstrate the utility of the present two Ti-crossed-Claisen condensations, we performed a couple of efficient short-step syntheses of two natural, representative, and useful perfumes, cis-jasmone and (R)-muscone.
authors.affiliation: Department of Chemistry, School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo, 669-1337, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Misaki
authors.forename: Ryohei
authors.initials: R
authors.lastname: Nagase
authors.forename: Kunshi
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Yoo
authors.initials: Y
authors.lastname: Tanabe
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry*; D003516:Cycloparaffins / Q000138:chemical synthesis; D003517:Cyclopentanes / Q000138:chemical synthesis; D004952:Esters / Q000138:chemical synthesis / Q000737:chemistry*; D007659:Ketones / Q000138:chemical synthesis*; D054883:Oxylipins
chemical_list: D002264:Carboxylic Acids; D003516:Cycloparaffins; D003517:Cyclopentanes; D004952:Esters; D007659:Ketones; D054883:Oxylipins; C086299:jasmone; C031021:muscone