Yang-Yin Xie, ‡. B. Wu, F. Xue
Aug 8, 1998
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0
Influential Citations
34
Citations
Journal
Organometallics
Abstract
A facile one-pot procedure for synthesizing isomerically pure bromothiophenes and bromobithiophenes was achieved by palladium-catalyzed hydrodebromination. The compounds synthesized include 2,3,4-tribromothiophene (2), 3,4-dibromothiophene (3), 2,3-dibromothiophene (7), 3-bromothiophene (4), 3,3‘,5-tribromo-2,2‘-bithiophene (10), 3,3‘-dibromo-2,2‘-bithiophene (11), and 3-bromo-2,2‘-bithiophene (12). The regioselectivity is catalytically dictated by the metalation site, whereas the extent of debromination is conveniently controlled by the stoichiometry and substrate quantity. Under favorable conditions, complete debromination takes place, giving rise to thiophene and bithiophene. The catalytic intermediates trans-PdBr(3,4-C4HBr2S-C)(PPh3)2 (16), trans,trans-Pd2Br2(μ-C8H2Br2S2-C,C‘)(PPh3)4 (17), trans,trans-Pd2Br2(μ-C8H4S2-C,C‘)(PPh3)4 (18), trans-PdBr(C8H4BrS2-C)(PPh3)2 (19), trans-PdBr(C4H3S-C)(PPh3)2 (20), and trans-PdBr(3,4,5-C4Br3S-C)(PPh3)2 (21) were isolated. Palladium insertion invariably occurs at ...