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The iridium-catalyzed C-H borylation of diethyl phenylphosphonate results in nonselective mono and bisborylation to afford a near statistical mixture of 3-, 3,5- and 4-boryl substituted aryl phosphonates whereas 3-substituted aryl phosphonates undergo highly regioselective C-H borylation to afford the corresponding meta-phosphonate substituted arylboronic esters as the sole product; the resulting boronic esters were used as nucleophilic reagents in a subsequent palladium-catalyzed Suzuki–Miyaura cross-coupling to generate a range of biarylmonophosphonates. Gratifyingly, the Suzuki–Miyaura cross-coupling can be conducted without purifying the boronic ester which greatly simplifies the synthetic procedure. [ABSTRACT FROM AUTHOR]

The synthesis of phosphinoboronate esters containing a single PB bond is reported, together with preliminary reactivity studies towards a range of organic substrates. These compounds add readily to aldehydes, ketones, aldimines, and α,β-unsaturated enones to give primarily the corresponding 1,2-addition products containing a new PC bond. The first examples of transition-metal-catalyzed phosphinoborations of C-C multiple bonds in which PC and BC bonds are formed in a single step are also disclosed; allenes react by a highly regioselective 1,2-addition whereas terminal alkynes undergo a formal 1,1-addition. [ABSTRACT FROM AUTHOR]

Thispaper reports the first examples of Suzuki–Miyauracross-couplings involving aryl- and naphthylphosphonate-based boronateesters as the nucleophilic partner. A systematic comparison of theperformance of biaryl-like KITPHOS- and XPHOS-based systems revealedthat, between them, an electronically and sterically diverse rangeof substrates can be coupled with remarkable efficiency to affordhigh yields of the corresponding biaryl and heterobiaryl monophosphonates.The use of an aryl- and naphthylphosphonate-based boronate ester asthe coupling partner presents an alternative and potentially complementarypathway to existing couplings in which the aryl- or naphthylphosphonateunit is typically introduced as the electrophile. The potential advantagesassociated with the use of this new class of coupling partner wereclearly demonstrated by the palladium-catalyzed reaction between diethyl[2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]phosphonateand 1-bromo-2-methoxynaphthalene that gave the correspondingbiaryl monophosphonate in 56% yield, a marked improvement on the 6%yield obtained from the reaction between 2-methoxy-1-naphthylboronicacid and diethyl (2-bromophenyl)phosphonate with the samecatalyst under the same conditions. The potential utility of thisnew coupling combination was demonstrated by reducing one of the products,2-methoxy-1-(2′-diethoxyphosphorylphenyl)naphthylene,to the corresponding primary phosphine, which was subsequently convertedinto a diastereoisomeric mixture of the R,R-hexane-2,5-diol-derived phospholane in reasonable yield. [ABSTRACT FROM AUTHOR]