Cobalt-Catalyzed syn Hydrophosphination of Alkynes
Hirohisa Ohmiya, Hideki Yorimitsu, Koichiro Oshima*
*Department of Material Chemistry, Graduate School of Engineering, Kyoto
University, Kyoto-daigaku Katsura, Nishikyo-ku, Kyoto, Email:
oshimaorgrxn.mbox.media.kyoto-u.ac.jp
H. Ohmiya, H. Yorimitsu, K. Oshima, Angew. Chem. Int. Ed., 2005, 44, 2368-2370.
DOI: 10.1002/anie.200500255
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Abstract
A stereoselective hydrophosphination reaction of alkynes with diphenylphosphane has been developed. The reaction is mediated by a cobalt catalyst and butyllithium.
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Details
The document discusses a cobalt-catalyzed syn hydrophosphination of alkynes developed by Hirohisa Ohmiya, Hideki Yorimitsu, and Koichiro Oshima. This method addresses the challenges in synthesizing organophosphorus compounds, which are crucial in various chemical fields. Traditional hydrophosphination methods using lanthanide complexes are efficient but require sensitive and complex preparations. The new method uses a cobalt salt and butyllithium, providing a straightforward, efficient, and general approach. The reaction proceeds in a syn fashion, complementing anti-selective radical hydrophosphination reactions. The process involves treating diphenylphosphane with butyllithium, followed by the addition of [Co(acac)2], dioxane, and an alkyne, and heating the mixture. The resulting products are obtained in high yields and are relatively insensitive to oxygen, simplifying their isolation and handling. Various alkynes were tested, showing high regioselectivity and exclusive formation of syn adducts. The method is scalable and applicable for synthesizing new ligands and advanced materials. The document also explores the utility of the hydrophosphination products in further chemical reactions, such as the Wittig reaction, offering a simple synthesis of conjugated dienes and related systems.
Key Words
alkenes, alkynes, cobalt, phosphines, thiophosphines, sulfidation, regioselectivity
ID: J06-Y2005-380