Synthesis of New Chiral P,S Hybrid Ligands and Their Use in Asymmetric Hydrosilylation of Ketones
Autor: | Atsuko Nishikawa, Manabu Hiraoka, Kazuo Achiwa, Toshiaki Morimoto |
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Rok vydání: | 1998 |
Předmět: | |
Zdroj: | Chemical and Pharmaceutical Bulletin. 46:704-706 |
ISSN: | 1347-5223 0009-2363 |
Popis: | Novel chiral P,S-hybrid ligands bearing 1,2-cis phosphinomethyl (or thiomethyl) and thio (or phosphino) groups on a cyclopentane skeleton were prepared by using borane as a protecting group for the phosphino group. Asymmetric hydrosilylation of acetophenone with 1 mol% of rhodium complex catalysts prepared in situ from [Rh(COD)Cl] 2 and P,S ligands, (1R,2R)-2-(diphenylphosphino)methyl-1-(phenylthio)cyclopentane (TPCP) and (1R,2S)-1-diphenylphosphino-2-[(phenylthio)methyl]cyclopentane (PTCP) gave the corresponding alcohols. The asymmetric hydrosilylation with the ligand TPCP showed higher enantioselectivity than that with PTCP or a diphosphine ligand (1R,2R)-1-(diphenylphosphino)-2-[(diphenylphosphino)methyl]cylopentane (PPCP). |
Databáze: | OpenAIRE |
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