Diastereoselective Palladium-Mediated Phosphetane Ring Opening and Pd-to-P Phenyl Migration. Synthesis of a New P-Stereogenic C₂-Symmetric Diphosphine Ligand

Abstract

Pd[(S,S)-Et-FerroTANE](Ph)(I) undergoes diastereoselective phosphetane ring opening with concomitant Pd-to-P phenyl migration on mild heating. Cleavage of the resulting palladacycle with acid yields Pd[FerroCHAIN]I2, whose reaction with PhMgBr leads to facile opening of the second phosphetane ring and isolation of a complex of a novel C 2-symmetric ligand with P and C stereocenters.

Synthesis of Chiral Heterocyclic Phosphines for Application in Asymmetric Catalysis

“…Additional studies by the Marinetti group showed that the ferrocenyl diphosphetanes 4 can also be advantageously used for the asymmetric Ru-catalyzed hydrogenation of -ketoesters [30]. Interestingly this catalytic system was not sensitive to the hydrogen pressure, whereas in the rhodium mediated hydrogenation of dehydroamino acid precursors a [32].…”

Palladacycle Chemistry on the Edge of Naphthalene and Triphenylene: Alkyne Cycloadditions and Autocatalytic Coupling

“…In contrast, the products for Pd are Pd black and Pd(PEt 3 ) 3 . While the analogous Pd alkyne complex Pd(PEt 3 ) 2 (η 2 -PhCCPh) is unknown, many analogues have been reported, − indicating that Pd(PEt 3 ) 2 (η 2 -PhCCPh) should exist but must be less stable than the Pt analogue and probably decomposes under the cycloaddition reaction conditions.…”

Transition metal-mediated metathesis between P–C and M–C bonds: Beyond a side reaction

“…Indeed, Glueck and coworkers reported the synthesis of new chiral phosphine ligands, which are otherwise hard to access, through Pd-mediated P-alkyl/Pd-phenyl exchange from phosphetane rings [68]. In a similar manner to the above-mentioned examples of the P-C bond cleavage from three and five-membered carbon-phosphorus heterocycles, four-membered carbon-phosphorus heterocycles [69] can also undergo facile P-C cleavage to give P-alkyl/Pd-phenyl exchanged palladacycles which can easily be transformed into complexes bearing novel bidentate ligands with both P and C stereogenic centers (Scheme 25).…”

“…The migration behaviors between M-R (R= alkyl [38,[55][56][57]59,61,66,68], allyl [48][49] and vinyl [89][90][91][92][93][94][95]) and P-Ar have also been studied for a long time. However, during P-Ar/Pd-Me exchange, there has been no evidence for the participation of the phosphonium intermediate [38].…”