Catalytic and Mechanistic Developments of the Nickel(II) Pincer Complex‐Catalyzed Hydroarsination Reaction

Abstract

Synthetic challengesh ave significantly slowed the development of the catalytic asymmetrich ydroarsination reaction despite it being ah ighly attractive CÀAs bond formation methodology.Ina ddition, there is ap oor understanding of the main reactions teps in such reactions which limit further developmenti nt he field.H erein, key intermediates of the hydroarsination reactionc atalyzed by aP CP Ni II -Cl pincer complex are presentedu pon investigating the reactionw ith DFT calculations, conductivity measurements, NMR spectros-copy,a nd catalytic screening.T he novel Ni-Cl-As interaction proposed was then contrasted against known Ni II -catalyzed hydrophosphination reactions to highlight dissimilaritiesb etweent hem even though Pa nd As share ac lose group relationship. Lastly,t he asymmetrich ydroarsination of nitroolefins was further developed to furnish al ibrary of chiral organoarsines in up to 99 %y ield and 80 % ee under mild conditions (À20 8CtoR T) between 5t o2 10 mins.[a] W.Product 5b:White solid;the ee was determined on aDaicel Chiralpak ID column with n-hexane/2-propanol = 99:1, flow = 0.8 mL min À1 ,w avelength = 254 nm;r etention times:8 .7 (minor), 9.6 min (major); 1 HNMR (CD 3 CN, 500 MHz): d = 7. 15 H, Ar), 4.98 (dd, 1H, 3 J HH = 13.1, 3 J HH = 13.1 Hz, AsCH), 4.62 (dd, 1H, 3 J HH = 13.6, 2 J HH = 3.8 Hz, NCH), 4.38 ppm (dd, 1H, 3 J HH = 12.6 Hz, 2 Conflict of interestThe authors declare no conflict of interest.

Broken Promises? On the Continued Challenges Faced in Catalytic Hydrophosphination

“…The significant advances in main-group chemistry over the last few decades have prompted interest in the heavier pnictogen congeners and their corresponding hydropnictogenation reactions. − Compared to the abundance of HP reports, these heavier hydrofunctionalization endeavors are still in their infancy, and the very act of catalytic hydrobismuthation (unreported to our knowledge) would be a remarkable achievement. However, while we can make a direct link between HP and the potential for novel ligand design, a relationship to applications of the heavier homologues is less clear.…”

Divergent Reactivity of Phosphapalladacycles toward E–H (E = N, P, As) Bonds

“…However, a straightforward H/D isotope exchange was previously identified to occur for secondary arsines under neutral conditions (Scheme ). Consequently, >99% ortho-deuterated phosphine 1′ was isolated when HAsPh 2 was prestirred in MeOD (entry 4). Similarly, >99% ortho-deuterated phosphine 1′ was also obtained when DAsPh 2 (derived from prestirring HAsPh 2 in MeOD) was reacted with complex 1a in toluene (entry 5).…”