1252804-16-2

Upstream product

• 1252804-13-9 [PdCl₂(5-bis(2-methoxyphenyl)phosphanyl-5H-dibenzo[a,d]cycloheptene)] 
• 16836-95-6 silver(I) 4-methylbenzenesulfonate 

Relevant academic research and scientific papers

Chemoselective methoxycarbonylation of terminal alkynes catalyzed by Pd(ii)-TROPP complexes

The mono-phosphanes 5-(diphenyl)-phosphanyl-5H-dibenzo[a,d]cycloheptene (TROPPPh) and 5-((2-methoxy)phenyl)-phosphanyl-5H-dibenzo[a,d] cycloheptene (TROPP(2-MeOPh)) have been employed to coordinate PdCl2, yielding [PdCl2(TROPPPh)] (1a) and [PdCl2(TROPP(2-MeOPh))] (1b), respectively. The corresponding tosylate (OTs) complexes [Pd(OTs)2(TROPPPh)] (2a) and [Pd(OTs)2(TROPP(2-MeOPh))] (2b) have been successfully applied in the p-benzoquinone (BQ)-assisted methoxycarbonylation of terminal alkynes to give chemoselectively the corresponding alkynylcarboxylic acid methyl ester with high TOF (up to 980 h-1). Unlike 2a/b, the PdII-(tosylate)-diphosphane complexes [Pd(OTs)(H2O)(dppp)] (OTs) 2c (dppp = 1,3-bis-di(phenylphosphanyl)propane and [Pd(H 2O)2(MeO-dppp)](OTs)22d (MeO-dppp = 1,3-bis(di(2-methoxyphenyl)phosphanyl)propane) preferentially catalyzed a double alkyne insertion. The "in situ" spectroscopic observation of the Pd-methoxycarbonyl compound [Pd(COOMe)(TROPPPh)](OTs) (3a) in conjunction with the evidence of the fast β-hydride elimination reaction of TROPP-based Pd-catalysts in the dimerization reaction of ethene are indicative for a strongly electrophilic metal centre. The X-ray crystal structures of 1a·0.5C2H4Cl2 and of the neutral and cationic Pd-alkyl complexes [Pd(Me)(Cl)(TROPPPh) (7a·0. 5CH2Cl2) and [Pd(CH2CH2COMe) (TROPPPh)](PF6) (10a·0.5C6H 6), respectively, confirm unambiguously the bidentate coordination mode of TROPP-ligands to PdII, that persists even in the presence of CO pressure. The Royal Society of Chemistry.