PN Bond Cleavage during the Insertion of Carbon Fragments into P^IIIN Bonds in Bis(diphenylphosphino) Amines

Abstract

The reaction of tertiary amine functionalized phosphines with aromatic and aliphatic aldehydes gives insertion of carbon fragments into the P III ÀN bonds or P III ÀN bond cleavage. The reaction of bis(diphenylphosphino) amines, 1a -1c, with two equiv. of aldehydes in toluene afforded the P III ÀN bond inserted products, 2a -4a, 4b -6b, and 3c -5c, in moderate-to-good yield. The products were characterized by IR, . This arises from several distinct advantages presented by PÀN containing ligands. Soft/hard assemblies such as P/N and P/O mainly act as donors to bind reversibly to a metal center, hence, providing or protecting temporarily a vacant coordination site, a characteristic property desired for catalysts. Earlier, we reported on the synthesis of a range of diphosphinoamine (PNP) ligands, and their catalytic behavior for the SuzukiÀHeck cross-coupling. Pd Complexes containing phosphino-amine ligands were shown to be excellent catalysts [3].Insertion of CO, alkene, alkyne, CO 2 , CS 2 , etc., into the MÀX bond (M ¼ metal or metal-like; X ¼ P, C, N, S, O, halide) are well-documented in the literature [4 -8]. Insertion of CO, alkene, etc., is an important step in many catalytic reactions, such as hydrogenation, hydroformylation [9 -11]. However, insertion of aldehydes into PÀN bonds is not a common reaction in chemical processes. Recently, Priya et al. reported the first insertion of C-fragments into PÀN bonds in the reaction of phosphino-amines with aldehydes, which led to the formation of a-amino phosphonates [12].The P

Functional Short-Bite Ligands: Synthesis, Coordination Chemistry, and Applications of N-Functionalized Bis(diaryl/dialkylphosphino)amine-type Ligands

“…In a recent study, Biricik et al have shown that the reaction of the DPPA derivatives 75 – 77 with aldehydes (2 equiv) led, after P–N bond cleavage, to the formation of their respective insertion products of general formula (Ph 2 PO)­CH­(R)­NH­[ x , y -(MeO) 2 C 6 H 3 ], ( x , y = 3,5; 2,5; 2,4; R = H, Me, Ph, C 6 H 4 OMe- p , C 6 H 4 Cl- p ) …”

“…Relevant structural parameters are reported in Table 7. 67 3.1.4. Other N-Functional Groups Containing an R− O−R′ Moiety.…”