Syntheses, structures, and reactions of cyrhetrenylphosphines; applications in palladium catalyzed Suzuki cross-coupling reactions
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- 作者：Diego Sierra ; Nattamai Bhuvanesh ; Joseph H. Reibenspies ; John A. Gladysz ; A. Hugo Klahn
- 关键词：Rhenium ; Lithiation ; Phosphines ; Palladium ; Suzuki coupling ; Crystal structures
- 刊名：Journal of Organometallic Chemistry
- 出版年：1 January, 2014
- 年：2014
- 卷：749
- 期：Complete
- 页码：416-420
- 全文大小：595 K
文摘
Reaction of bromocyrhetrene (畏5-C5H4Br)Re(CO)3 with lithium tetramethylpiperidide (LiTMP; 1.0聽equiv,聽鈭?8聽掳C) and then ClPR2 (R聽=聽a, Ph; b, Cy) gives (畏5-1,2-C5H3BrPR2)Re(CO)3 (5a, 48%; 5b, 80%). Analogous reactions with 2.0聽equiv of LiTMP and ClPR2 give the 1-bromo-2,5-diphosphidocyclopentadienyl complexes [畏5-1,2,5-C5H2Br(PR2)2]Re(CO)3 (6a, 60%; 6b, 80%). These rhenium containing or cyrhetrenylphosphines are combined with Pd(OAc)2 (2:1聽mol ratio) to give catalysts for Suzuki couplings of phenylboronic acid and p-bromotoluene or p-bromoacetophenone (1聽mol%; Cs2CO3, toluene, 100聽掳C). The catalyst with 5b exhibits much higher activities than the others, with conversions of 92-64% after 20聽min. The crystal structures of 5b and 6a,b are determined.