(Z)- or (E)-Selective Hydrogenation of Potassium (3,3,3-Trifluoroprop-1-yn-1-yl)trifluoroborate: Route to Either Isomer of β-Trifluoromethylstyrenes
P. Veeraraghavan Ramachandran* and Wataru Mitsuhashi
*Herbert C. Brown Center for Borane Research, Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States, Email: chandranpurdue.edu
P. V. Ramachandran, W. Mitsuhashi, Org. Lett., 2015, 17, 1252-1255.
DOI: 10.1021/acs.orglett.5b00235 (free Supporting Information)
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A Pd-catalyzed hydrogenation of potassium (3,3,3-trifluoroprop-1-yn-1-yl)trifluoroborate provides either the (Z)- or (E)-isomer of the vinylborate in >98% purity. Coupling with bromo- and iodoarenes provides a variety of (Z)- or (E)-β-trifluoromethylstyrenes. Also, a safe synthesis of the alkynyltrifluoroborate has been described.
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