Rhodium‐Catalyzed Enantioposition‐Selective Hydroarylation of Divinylphosphine Oxides with Aryl Boroxines

Abstract

The rhodium-catalyzed hydroarylation of divinylphosphine oxides (RP(O)(CH=CH ) ) with aryl boroxines ((ArBO) ) gives the corresponding monoarylation products (RP(O)(CH=CHAr)CH CH ) in high yields. One of the two vinyl groups in the phosphine oxide undergoes oxidative arylation while the other one is reduced to an ethyl moiety. These reactions proceed with high selectivity in terms of the enantiotopic vinyl groups in the presence of (R)-DTBM-segphos/Rh to give the P-stereogenic monoarylation products with high enantioselectivity.

Synthesis of meta‐Arylated Phenol Derivatives by Rhodium(I)‐Catalyzed Arylation of Quinone Monoacetal

“…Product 4 a was produced by hydrolysis of the corresponding intermediate A , while hydrolysis of intermediate C would generate product 5 a . It is noteworthy that the formation of reductive Heck‐type product like 5 a via intramolecular hydrogen transfer is quite rare, and a similar type of transformation using divinylphosphine oxides as the substrates was recently disclosed by the Hayashi group …”

Asymmetric Catalytic 1,2‐Dihydrophosphination of Secondary 1,2‐Diphosphines – Direct Access to Free P*‐ and P*,C*‐Diphosphines

“…Given its potential, we sought to apply the protocol in the synthesis of P ‐chiral diphosphines since these compounds could induce greater enantiocontrol due to increased proximity between the projecting groups at phosphorus and the activated substrate . To the best of our knowledge, access to these trivalent phosphorus species by catalytic means are restricted to enantioselective deprotonation protocols, asymmetric alkylation, and catalytic desymmetrisation of phosphine oxides …”

Efficient Oxidative Resolution of 1-Phenylphosphol-2-Ene and Diels–Alder Synthesis of Enantiopure Bicyclic and Tricyclic P-Stereogenic C-P Heterocycles

“…The most spectacular example of their utility has been the use of (S P )-PAMP {o-anisylmethylphenylphosphine} and (R P ,R P )-DIPAMP {1,2-bis(o-anisylmethylphenylphosphine)ethane} di as chiral ligands in rhodium-catalyzed asymmetric hydrogenation of enamides [5] which led to the first application of such a process in the industrial production, i.e., the Monsanto L-DOPA process [6] However, P-stereogenicity is not a natural phenomenon, and, from the very beginning [7], it had to be generated in the lab. Despite many developed asymmetric syntheses [1,[7][8][9][10][11][12][13][14][15][16][17][18], desymmetrizations [14,[19][20][21][22][23][24][25][26][27] and kinetic resolutions [28][29][30][31][32][33][34], practical preparations of optically active P-stereogenic compounds are still relying in great part on classical resolution of racemates [7,8,[35][36][37][38][39][40]. The latter has the advantage to rely on cheap and often recoverable chiral auxiliaries, uses crystallization for separation of the P-epimers and, The subsequent resolution of rac-1 started with its reduction to the corresponding phosphine 2 by treatment with PhSiH 3 at the t...…”