Styryl boronic ester

P-Substituted vinylboronic esters were isolated in fair to high yields from the coupling under classical Heck conditions of vinylBhg with (hetero)aryl iodides and bromides (Table 3.1, entries 1-3). A dienyl boronic ester was obtained by coupling of vinylBhg with a vinyl iodide derived from phenylgly-cine (entry 4). The preparation of a styryl boronic ester with a sulfonamide moiety is described in a patent (entry 5) this product was later used in a Suzuki-Miyaura reaction. ... 

Scheme 3.23 Suzuki-Miyaura reaction with a styryl boronic ester. (Adapted with permission from ref. 90 2013 American Chemical Society.)...

Pietruszka has reported the synthesis of styryl and cyclopropyl boronic esters with an acrylate functionality by applying a cross-metathesis reacTion (%]. Thus, the reaction of cyclopropyl boronate 122 with methyl acrylate gave the E-enoate 123 in 52% yield (Scheme 3.63). 

A standard way to make vinyl boronic acids 237 is to hydroborate an alkyne with catechol borane38 235 and again hydrolyse the ester products 236. The empty orbital of the boron atom attacks the electron-rich terminus of the alkyne where is the larger HOMO of the Jt-bond. One detailed example39 includes Suzuki coupling to Z-styryl bromide. Another diester group commonly used in the Suzuki coupling is derived from pinacol - examples appear later. 

There has been a wide-ranging review of transmetalation reactions of arenes concentrating on the use of boron-containing compounds. The reaction of arylboronate esters and related compounds with alkyl halides is catalysed by copper(I) formation of an aryl—copper intermediate followed by an 5N2-type reaction with the alkyl electrophile is likely. Palladium complexed with a diimine is an excellent catalyst in the phenylation reaction of Michael acceptors with phenylboronic acid so as to yield products such as (16). The nickel-catalysed reaction of phenylboronic acid with styryl epoxides has been shown to yield a-substituted alcohols such as (17). 

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