Unusual Palladium-Catalyzed Silaboration of Allenes Using Organic Iodides as Initiators: Mechanism and Application

Kuo-Jui Chang, Dinesh Kumar Rayabarapu, Feng-Yu Yang and Chien-Hong Cheng*

*Department of Chemistry, Tsing Hua University, Hsinchu, 30013 Taiwan, Email: chchengmx.nthu.edu.tw

K.-J. Chang, D. K. Rayabarapu, F.-Y. Yang, C.-H. Cheng, J. Am. Chem. Soc., 2005, 127, 126-131.

DOI: 10.1021/ja044662q

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Abstract

A highly regio- and stereoselective palladium-catalyzed synthesis of various 2-silylallylboronates from allenes and 2-(dimethylphenylsilanyl)-4,4,5,5-tetramethyl[1,3,2]dioxaborolane afforded the corresponding silaboration products in moderate to excellent yields. In the absence of an organic iodide, the silaboration gives products having completely different regiochemistry. In the presence of an aldehyde, the silaboration reaction afforded homoallylic alcohols in one pot in good to excellent yields, with exceedingly high syn selectivity.

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Highly Regio- and Stereoselective Acylboration, Acylsilation, and Acylstannation of Allenes Catalyzed by Phosphine-Free Palladium Complexes: An Efficient Route to a New Class of 2-Acylallylmetal Reagents

F.-Y. Yang, M. Shanmugasundaram, S.-Y. Chuang, P.-J. Ku, M.-Y. Wu, C.-H. Cheng, J. Am. Chem. Soc., 2003, 125, 12576-12583.

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Key Words

Allenes, Borylation, Vinylsilanes, Silaboration, Homoallylic Alcohols

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ID: J48-Y2005-2160