Allylboronic acid pinacol ester

Scheme 20 Reactivity of 29 in Suzuki-Miyaura coupling of allylboronic acid pinacol ester derivatives...

The desired diene-containing compounds such as 48 can also be synthesized using the Suzuki-Miyaura cross-coupling reaction. For example, cross-coupling of the aromatic diiodide 49 with allylboronic acid pinacol ester 50 readily furnished 48 [23]. After exposure of this diene 48 to an RCM reaction, followed by DDQ oxidation, the naphthalene 51 was produced in good yield (Scheme 17.8). 

SCHEME 17.8 Synthesis of substituted naphthalenes from 1,2-diiodobenzenes—application of allylboronic acid pinacol ester. (Adapted with permission from Ref. [10]. Copyright (2009) American Chemical Society). 

Conjugate addition of allylboronic acid pinacol ester to nons)mimet-ric dialkylidene ketones with an in situ generated phosphonite nickel catalyst. 

The aoss-coupling reaction of bis(pinacolato)diboron with allyl acetates provides the pinacol esters of allylboronic acids in high yield (Scheme The reaction is effectively catalyzed by Pd(dba)2 in DMSO at 50 °C. The reaction more or less accompanies the formation of biallyl, the amount of which markedly depends on the kind of leaving group of the al-lyhc substrates. E)- and (Z)-Cinnamyl acetate and a-phenylallyl acetate aU provide trans-cinnamylboronic acid ester selectively and in almost the same yield, which suggests that the reaction proceeds via ir-allylpalladium as a common intermediate. 

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