Functional group chemistry at intramolecular frustrated Lewis pairs: substituent exchange at the Lewis acid site with 9-BBN†
Abstract
The vicinal frustrated P/B Lewis pair (FLP) Mes2PCH2CH2B(C6F5)2 reacts with 9-borabicyclo[3.3.1]nonane (9-BBN) by C6F5vs. H exchange at boron to give the new [B]–H functionalized FLP Mes2PCH2CH2B(H)(C6F5) (4) and 9-C6F5–BBN. The latter was characterized as an isonitrile adduct by X-ray diffraction. The new FLP 4 forms an adduct with pyridine and it undergoes clean hydroboration reactions with 1-pentyne or added styrene or dimesitylvinylphosphane. The products formed stable adducts with pyridine; two such examples were also characterized by X-ray crystal structure analysis. A similar alkyl vs. hydrogen exchange was observed upon treatment of an Al/N based Lewis pair, iBu2Al–(Me3Si)CC(H)–N(CH2CH2)2NMe (14), with 9-BBN.
- This article is part of the themed collection: Boranes and borohydrides