The iterative synthesis of oligoarenes via an organoborane-based cross-coupling reaction (i.e., the Suzuki−Miyaura coupling) has been achieved by using a series of “masked” haloarylboronic acids as building blocks whose ordinarily reactive boronyl groups are temporarily protected by a new masking group derived from 1,8-diaminonaphthalene.

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A differentially protected diboron bearing the naphthalene-1,8-diaminato group on one of the two boron atoms undergoes highly regioselective diboration with terminal alkynes in the presence of Pt or Ir catalysts, giving 1-alkene-1,2-diboronic acid derivatives in which the less reactive B(dan) group is located at the terminal position. The products undergo selective Suzuki-Miyaura coupling with aryl bromides at the internal boronyl group, leading to the formation of 2,2-disubstituted alkenylboronic acid derivatives.

(Triorganosilyl)pinacolboranes were prepared by reaction of triorganosilyllithium reagents with pinacolborane or isopropoxypinacolborane in high yield. The reaction also is applicable to synthesis of 2-(triorganosilyl)-4,4,6-trimethyl-1,3,2-dioxaborinane. A new germylborane derivative was similarly prepared from the corresponding germyllithium.

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