Arylation of 6H-dibenzo[c,e][1,2λ5]oxaphosphinine 6-oxide

Abstract

Arylation and alkylation of 6H-dibenzo[c,e][1,2λ 5 ]oxaphosphinine 6-oxide at the phosphorus atom was accomplished. Tetrafluoro-4-pyridyl fragment was introduced via reaction of 6-trimethylsiloxy-6H-dibenzo[c,e][1,2]oxaphosphinine with pentafluoropyridine. The arylation of the title compound with aryl iodides containing both electron-acceptor and electron-donor substituents was effected under catalysis by palladium or nickel complexes.

Phosphorus‐Carbon Bond Formation: Palladium‐Catalyzed Cross‐Coupling of H‐Phosphinates and Other P(O)H‐Containing Compounds

“…Beletskaya and co‐workers studied the arylation of DOPO with iodides and bromides and 5 mol% palladium. The isolated yields were in the 75% range with iodides, and 50% with 4‐NCC 6 H 4 Br 11t. Using our conditions, DOPO reacts uneventfully in moderate yields, as shown in Table 6.…”

Preparation of Arylphosphonates by Palladium(0)‐Catalyzed Cross‐Coupling in the Presence of Acetate Additives: Synthetic and Mechanistic Studies

“…The most commonly used one is triethylamine, [23] however, due to possible dealkylation of sensitive H-phosphonate diesters, it is often replaced by less nucleophilic tertiary amines [22,24] or propylene oxide. [9,12,20] For special reaction conditions, for example, biphasic conditions [25] or for the reactions involving microwave heating, [26] using inorganic bases such as K 2 CO 3 and Cs 2 CO 3 can be advantageous. As far as the palladium source is concerned, it was found that in contrast to PdA C H T U N G T R E N N U N G (PPh 3 ) 4 used in Hiraos original procedure, [1] catalytic systems generated in situ from PdA C H T U N G T R E N N U N G (OAc) 2 and appropriate phosphine ligands, were usually superior in terms of reactivity for promoting the C À P bond formation.…”

A Highly Diastereoselective Route to Dinaphtho[c,e][1,2]oxaphosphinines and Their Application as Ligands in Homogeneous Catalysis

“…Dibenzo[c,e] [1,2]oxaphosphinines, investigated by the Keglevich group, [6] for example, are useful substrates for Pd-and Ni-catalysed arylations. [7] These heterocycles have also been used as ligands in the Ni-catalysed hydrocyanation of butadienes [8] and in the regioselective Rh-catalysed hydroformylation of olefins. [9] Moreover, they were employed as additives to enhance the thermal stability of polymers.…”

“…[11] Later on, Pastor et al suggested a one-pot synthesis involving cyclization of 1 in PCl 3 with ZnCl 2 as catalyst at high temperature. [12,13] The chloro compound 3 [6][7][8][9][10][11][12] represents an interesting starting material for subsequent substitution reactions on the trivalent phosphorus. Inspired by these results and as part of our ongoing studies concerned with the synthesis of chiral P-ligands, [14] we became interested in the synthesis of sterically more hindered compounds such as the binaphthyl [1,2]oxaphosphinines 7 (Scheme 2).…”