Highly Efficient Palladium-Catalyzed Arsination. Synthesis of a Biphenyl Arsine Ligand and Its Application to Obtain Perfluoroalkylarsines

Synthetic Strategy for AB2-Type Arsines via Bidentate Dithiolate Leaving Groups

Despite their potential for several transition-metal-catalyzed reactions, arsenic ligands are poorly diversified. In this work, we developed an efficient synthetic methodology for AB₂-type ligands, which is a typical motif in phosphorus systems, for example, in Buchwald ligands. The introduction of 1,2-benzenedithiol to tribromoarsine reduces the reactivity of two of the three reaction sites. After the substitution reaction with the first nucleophile involving the elimination of bromide, the substitution reaction with the second nucleophile produced AB₂-type arsines through the elimination of the dithiolate anion. Among the various types of obtained AB₂-type arsines, the arsa-Buchwald ligands, which are arsenic analogues of Buchwald ligands, were applied to the Suzuki-Miyaura cross-coupling reaction. Some of the arsa-Buchwald ligands showed activity comparable to that of the well-known Buchwald ligand, SPhos. Furthermore, the arsenic analogue of SPhos showed higher activity and stability than SPhos under open-air conditions.

Inorganometallics (Transition Metal-Metalloid Complexes) and Catalysis

While the formation and breaking of transition metal (TM)–carbon bonds plays a pivotal role in the catalysis of organic compounds, the reactivity of inorganometallic species, that is, those involving the transition metal (TM)–metalloid (E) bond, is of key importance in most conversions of metalloid derivatives catalyzed by TM complexes. This Review presents the background of inorganometallic catalysis and its development over the last 15 years. The results of mechanistic studies presented in the Review are related to the occurrence of TM–E and TM–H compounds as reactive intermediates in the catalytic transformations of selected metalloids (E = B, Si, Ge, Sn, As, Sb, or Te). The Review illustrates the significance of inorganometallics in catalysis of the following processes: addition of metalloid–hydrogen and metalloid–metalloid bonds to unsaturated compounds; activation and functionalization of C–H bonds and C–X bonds with hydrometalloids and bismetalloids; activation and functionalization of C–H bonds with vinylmetalloids, metalloid halides, and sulfonates; and dehydrocoupling of hydrometalloids. This first Review on inorganometallic catalysis sums up the developments in the catalytic methods for the synthesis of organometalloid compounds and their applications in advanced organic synthesis as a part of tandem reactions.

C-As Bond Formation Reactions for the Preparation of Organoarsenic(III) Compounds

Potential widespread applications of organoarsenic chemistry have been limited by the inherent lack of safe and effective As-C bond formation reactions. Several alternative reagents and methods have been developed in the last few decades to address the hazards and drawbacks associated with traditional arsenic synthetic strategies. Herein, this minireview summarizes the advances made in nucleophilic, electrophilic, radical and metal-mediated As(III)-C bond formations while specifically highlighting the behavior of arsenic synthons with various well-established reagents (eg. Grignard reagents, organolithium compounds, organometallic reagents, radical initiators and Lewis/Brønsted bases). Avenues for asymmetric synthesis are also discussed, as are recent advances in organoarsenic chemistry suggesting that arsines exhibit novel reactivities independent from that of other relatively more well explored Group V cogeners.

Investigating palladium pincer complexes in catalytic asymmetric hydrophosphination and hydroarsination

Given the periodic relationship of phosphines and arsines, is remodeling the catalytic asymmetric hydrophosphination reaction an efficient manner to develop the corresponding hydroarsination reaction? Herein, a chiral PCP-Pd(ii) pincer complex adept at generating enantioenriched phosphines was examined in the asymmetric hydroarsination reaction. Under distinct conditions, tertiary phosphines and arsines were generated in excellent yields (P: 96%, As: 91%) and ees (P: 90%, As: 85%). While secondary arsine reagents were not direct substitutes for the analogous phosphines, important parameters were identified which increased yield and ee of the hydroarsination reaction. Unlike the PCP-PdOAc pincer complex commonly used for hydrophosphinations, hydroarsination reactions involved a PCP-PdCl catalyst with 10 equiv. of CsF for optimal performance. Notable differences between the two reactions and their workup procedures were highlighted to guide further developments in the field. Lastly, respective mechanisms were proposed and contrasted for the activation of HEPh2 (E = P, As).

Study of the dual functional behaviour of 1,2-bis(4-bromobenzamide)benzene by synchronous fluorescence spectroscopy

This study presents the dual functionality of 1,2-bis(4-bromobenzamide)benzene, where depending on the stoichiometric conditions, temperature and reaction time, the compound may act as a PdCl₂ ligand or as one of the reactants of the Suzuki coupling reaction.