Soft Propargylic Deprotonation: Designed Ligand Enables Au-Catalyzed Isomerization of Alkynes to 1,3-Dienes
Zhixun Wang, Yanzhao Wang and Liming Zhang*
*Department of Chemistry & Biochemistry, University of California, Santa Barbara, California 93106, United States, Email: zhangchem.ucsb.edu
Z. Wang, Y. Wang, L. Zhang, J. Am. Chem. Soc., 2014, 136, 8887-8890.
DOI: 10.1021/ja503909c (free Supporting Information)
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A biphenyl-2-ylphosphine with a basic amino group at the 3′ position possesses orthogonally positioned "push" and "pull" forces, that enable a gold(I)-catalyzed soft propargylic deprotonation and permit the bridging of a difference of >26 pKa units (in DMSO) between a propargylic hydrogen and a protonated tertiary aniline. This design led to efficient isomerization of alkynes into versatile 1,3-dienes with synthetically useful scope under mild reaction conditions.
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