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Synthesis and Properties of Bis(2-heteroaryl)borane Derivatives

2002; Wiley; Volume: 2002; Issue: 11 Linguagem: Inglês

10.1002/1099-0682(200211)2002

1099-0682

Thomas Köhler, Jürgen Faderl, Hans Pritzkow, Walter Siebert,

Chemical Synthesis and Reactions

The reaction of (isopropyloxy)bis(2-thienyl)borane (1d) with Grignard reagents leads to methylbis(2-thienyl)borane (1e) and to phenylbis(2-thienyl)borane (1f). Treatment of monolithiated heterocycles with dichloroboranes yields the bis(2-heteroaryl)boranes 1b, 1c, and 3a, which are dibrominated with NBS to give the 5,5′-dibromo products 1b′, 2a′, and 3a′. NMR spectroscopic and MS data confirm the composition of the compounds. The [2+2] cyclization of the dibromo derivatives yields, in the case of 2a′, the macrocycle 4b, as confirmed by HR-MS data. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)