title: Rhodium-catalyzed carbon-silicon bond activation for synthesis of benzosilole derivatives.
abstract: A rhodium-catalyzed coupling reaction of 2-trimethylsilylphenylboronic acid with internal alkynes is developed for the synthesis of 2,3-disubstituted benzosilole derivatives. A range of functional groups, encompassing ketones, esters, amines, aryl bromides, and heteroarenes, are compatible, which provides rapid access to diverse benzosiloles. Sequential 2-fold coupling enables modular synthesis of asymmetrically substituted 1,5-dihydro-1,5-disila-s-indacene, a π-extended molecule of interest in organic electronics. In terms of the mechanism, the reaction involves cleavage of a C(alkyl)-Si bond in a trialkylsilyl group, which normally requires extremely harsh conditions for activation. Mechanistic studies, including effects of substituents, reveal that C-Si bond cleavage does not proceed through a hypercoordinated silicon species, but rather through a rhodium-mediated activation process. The potential use of the reaction in catalytic asymmetric synthesis of Si-chiral benzosiloles is also demonstrated.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Onoe
authors.forename: Katsuaki
authors.initials: K
authors.lastname: Baba
authors.forename: Yoonjoo
authors.initials: Y
authors.lastname: Kim
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kita
authors.forename: Mamoru
authors.initials: M
authors.lastname: Tobisu
authors.forename: Naoto
authors.initials: N
authors.lastname: Chatani
mesh_terms: D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D017646:Organosilicon Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D012238:Rhodium / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D017646:Organosilicon Compounds; D002244:Carbon; D012238:Rhodium; D012825:Silicon