Hydroborylation of monocoordinated phosphorus

Hydroboration of Phosphaalkynes by HB(C6F5)2

“…This pattern of reactivity stands in contrast to literature reports of B-H, [17] Ge-H, [18] and Sn-H [19] phosphaalkyne addition reactions, in which hydride adds to the more electropositive phosphorus affording a P-H bond. Interestingly, the formation of 2a is more akin to reactions of phosphaalkynes with Ru-H species described by Hill, Jones [27] and Crossley, [28] reinforcing the analogy between electrophilic boranes and transition metals.…”

“…Aside from Ti species B , the direct addition of an R 2 B−H bond to a phosphaalkyne has been reported only once, to the best of our knowledge. In that example, the double hydroboration of tert‐ butylphosphaalkyne ( t BuC≡P, 1 a ) with HBCat (Cat=catechol) generated a gem ‐diboryl substituted primary phosphine (Figure , C ) . The regiochemistry of this 1,2‐addition reaction is governed by the electronegativity difference between carbon and phosphorus and the inherent polarity of the δ+ P≡C δ− bond.…”

“…In that case, the double hydroboration of tert-butylphosphaalkyne (tBuCP 1a) with HBCat (Cat = catechol) generated a gem-diboryl substituted primary phosphine (Figure 1, C). [17] The regiochemistry of this 1,2-addition reaction is governed by the electronegativity difference between carbon and phosphorus and the inherent polarity of the δ+ PC δ-bond This regiochemistry of 1,2-addition has also been observed in related hydrogermylation [18] and hydrostannation chemistry. [19] In contrast, the aforementioned reaction of HBEt2 with a Ti-phosphaalkyne complex resulted in B-P bond formation.…”

Linkage Isomerism Leading to Contrasting Carboboration Chemistry: Access to Three Constitutional Isomers of a Borylated Phosphaalkene

“…NMR spectra were acquired on aB ruker AVIII 500 MHz NMR spectrometer ( 1 H5 00 MHz, 13 Synthesis of E-[B]O{(C 6 F 5 ) 2 B}C=P(C 6 F 5 )( 1): Tris(pentaflourophenyl)borane (110 mg, 0.22 mmol) was added to as olution of [B]OCP (100 mg, 0.22 mmol) in toluene (3 mL). The solution immediately changed colour from pale yellow to red.…”

“…[7,8] In the case of tris(pentafluorophenyl)borane, related reactions are only possible using more reactive substrates, such as allenyl ketones and isocyanates. [9][10][11][12] It is these latters tudies, as well as relatedw ork exploring the hydroboration of phosphaalkynes, [13][14][15] that prompted us to explore the reactivityo fB CF towardst wo isomericf orms of ab oryl-phosphaethynolate, [B]OCPa nd [B]PCO( where [B] = N,N'-bis(2,6-diisopropylphenyl)-2,3-dihydro-1H-1,3,2-diazaboryl). [16,17] Interestingly,t hese reactions give rise to three different borylatedp hosphaalkenes with the same molecular formula.…”