Rhodium catalysed dehydrogenative borylation of alkenes: vinylboronates via C-H activation.

We present herein a high yield, highly selective catalytic synthesis of vinylboronate esters (VBEs), including 1,1-disubstituted VBEs, from alkenes without significant hydrogenation or hydroboration, using the simple catalyst precursor, trans-[RhCl(CO)(PPh3)2] (1), and the diboron reagents B2pin2 (2a, pin = pinacolato = OCMe2CMe2O) or B2neop2 (2b, neop = neopentylglycolato = OCH2CMe2CH2O), or the monoboron reagent HBpin, all of which are commercially available. The reactions were conducted at 80 degrees C using conventional heating, or in a microwave reactor at 150 degrees C.

Selective Ir-catalysed borylation of polycyclic aromatic hydrocarbons: structures of naphthalene-2,6-bis(boronate), pyrene-2,7-bis(boronate) and perylene-2,5,8,11-tetra(boronate) esters.

The selectivity of the iridium boryl complex-catalysed reaction of pyrene and perylene with B2(pin)2 (pin = OCMe2CMe2O) has been employed in the synthesis of D(2h)-symmetry pyrene-2,7-(Bpin)2 and D(4h)-symmetry perylene-2,5,8,11-(Bpin)4 providing direct borylation of positions which are otherwise difficult to derivatise.