Platinum(0)-catalyzed diboration of alkynes

An Alkyne Diboration/6π‐Electrocyclization Strategy for the Synthesis of Pyridine Boronic Acid Derivatives

“…The synthesis of pyridines via 6p-electrocylization reactions represents an interesting and alternative means for the bespoke synthesis of this class of heterocyclic intermediates, and the reaction is compatible with a range of common functional groups such as esters, aldehydes and ethers. [5,6] Importantly, in the context of boronic acid derivatives, we envisaged that we could take advantage of catalytic diborylation methodology [7] to transform readily available yne-ene-oximes into pyridine boronic esters. As shown in Scheme 1, central to our objective was the activation of the alkynes substrate towards electrocyclization whilst simultaneously incorporating useful functionality.…”

(μ2-Pinacolato-O,O')-bis(pinacolato-O,O')diboron

“…The compound B2pin2 is of interest with regard to the recently developed metalcatalysed diboration of alkynes (Ishiyama, Matsuda, Miyaura & Suzuki, 1993;Iverson & Smith, 1995Ishiyama et al, 1996;Lesley et al, 1996) and alkenes (Baker, Nguyen, Marder & Westcott, 1995) and the palladium-catalysed synthesis of (aryl)B(pin) compounds (Ishiyama, Murata & Miyaura, 1995). It appears that B2pin3 is also formed in reactions of pinacol with BH3.thf or BC13 (Herberich & Fischer, 1996).…”

Bis(pinacolato)diboron

“…In 1993, Miyaura's group reported the first platinum(0)-catalyzed vic-diboration of alkynes using bis(pinacolato) diboron (1). 2 This group subsequently expanded the substrates to alkenes, 1,3-dienes, allenes, and a,b-unsaturated ketones. 3 These reactions provide new alternatives to access the funcational organoboron compounds and also popularized diboron 1 as a new boron source.…”