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Arylethyne Bromoboration–Negishi Coupling Route to E ‐ or Z ‐Aryl‐Substituted Trisubstituted Alkenes of ≥98% Isomeric Purity. New Horizon in the Highly Selective Synthesis of Trisubstituted Alkenes
Author(s) -
Wang Chao,
Xu Zhaoqing,
Tobrman Tomas,
Negishi Eiichi
Publication year - 2010
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200900766
Subject(s) - chemistry , negishi coupling , pinacol , regioselectivity , aryl , alkyne , palladium , combinatorial chemistry , catalysis , tandem , medicinal chemistry , organic chemistry , alkyl , materials science , composite material
The hitherto unprecedented palladium‐catalyzed cross‐coupling of ( Z )‐β‐bromo‐β‐arylethenylboranes can be made to proceed satisfactorily through (1) the use of highly catalytically active bis(tri‐ tert ‐butylphosphine)palladium or dichloro[ N , N ‐bis‐(2,6‐diisopropylphenyl)imidazol‐2‐yl]( m ‐chloropyridine)palladium and (2) conversion of the dibromoboryl group to the (pinacol)boryl group. Thus, a wide variety of carbon groups can be used to substitute bromine in ≥98% stereo‐ and regioselectivity, while suppressing the otherwise dominant β‐debromoboration. Together with the alkylethyne‐based protocols, the alkyne bromoboration–Negishi coupling tandem process has emerged as the most widely applicable and highly selective route to trisubstituted alkenes including those that are otherwise difficult to access.