19938-06-8Relevant academic research and scientific papers
Synthesis of tetra-pincer nickel(ii) and palladium(ii) complexes of resorcin[4]arene-octophosphinite [Res(OPR2)8] and rhodium-catalyzed regioselective hydroformylation reaction
Ananthnag, Guddekoppa S.,Mondal, Dipanjan,Mague, Joel T.,Balakrishna, Maravanji S.
, p. 14632 - 14641 (2019/10/16)
The condensation reaction of resorcinol with pentanal yielded resorcin[4]arene 1 which on bromination using N-bromosuccinimide at room temperature produced tetra-bromide derivative 2. The reactions of 2 with chlorodiphenylphosphine and o-phenylenephosphoro-chloridite yielded octaphosphinite 3 (hereafter referred to as octaphos) and octaphosphite 4, respectively. The reactions of 3 with Ni(COD)2 or Pd2(dba)3·CHCl3 in appropriate molar ratios yielded tetra-pincer complexes 5 and 6, respectively. The structures of both the complexes were established by single crystal X-ray diffraction studies. The resorcin[4]arene backbone adopts a boat structure in these complexes. Typically, the Rh-catalyzed hydroformylation of styrene prevalently delivers a branched (b) chiral aldehyde. A unique resorcin[4]arene skeleton based octaphos 3 was employed in the Rh-catalyzed hydroformylation of styrene. The hydroformylation of styrene with a metal to ligand ratio of 1:1 (M:L) was found to be regioselective, producing a linear (l) aldehyde as a major product with 100% conversion in 3 h. The l:b ratio surprisingly increased when the ortho positions of styrene were populated by methyl and chloro substituents. The hydroformylation of p-nitro styrene triggered a remarkably high linear:branched aldehyde ratio of 2.4 (71% linear aldehyde) despite its electron withdrawing nature. The highest linear selectivity of 97% (l:b ratio 27.8) was achieved in the case of 2,4,6-trimethylstyrene.
An Effective Pd-Catalyzed Regioselective Hydroformylation of Olefins with Formic Acid
Ren, Wenlong,Chang, Wenju,Dai, Jie,Shi, Yuan,Li, Jingfu,Shi, Yian
supporting information, p. 14864 - 14867 (2016/11/29)
An effective palladium-catalyzed regioselective hydroformylation of olefins with formic acid is described. The ligand plays a crucial role in directing the reaction pathway. Linear aldehydes can be obtained in up to 93% yield with >20:1 regioselectivity using 1,3-bis(diphenylphosphino)propane (dppp) as the ligand. The reaction process is operationally simple and requires no syngas.
Replacing a stoichiometric silver oxidant with air: Ligated Pd(II)-catalysis to β-aryl carbonyl derivatives with improved chemoselectivity
Vellakkaran, Mari,Andappan, Murugaiah M.S.,Kommu, Nagaiah
supporting information, p. 2788 - 2797 (2014/05/06)
Air was employed as a green reoxidant of Pd(0), replacing stoichiometric and toxic silver salt, in the chelation-controlled Pd(II)-modulated arylative enolization of prop-2-en-1-ols to acquire synthetically-important β-aryl carbonyl derivatives. This green approach, which didn't require acid or base, allowed the compatibility of a range of functionalities (inclusive of -I, -Br & -Cl), resulting in the construction of structurally-diverse dihydrochalcones, α-benzyl-α′-alkyl acetones, α-benzyl β-keto esters and dihydrocinnamaldehydes. In addition to organoboronic acids, efficient coupling was also achieved with boronic esters and trifluoroborate salts. A deuterium labelling experiment revealed an interesting 1,2-hydrogen shift after β-arylation in the catalytic process. the Partner Organisations 2014.
Ligated regioselective PdII catalysis to access β-aryl-bearing aldehydes, ketones, and β-keto esters
Vellakkaran, Mari,Andappan, Murugaiah M. S.,Kommu, Nagaiah
supporting information; experimental part, p. 4694 - 4698 (2012/09/22)
By employing ligands in the PdII-mediated arylative isomerization of allyl alcohols, a milder and regioselective access to the versatile building blocks β-aryl aldehydes and ketones was developed. This new and chelation-controlled protocol enabled the compatibility of wide range of functionalities to generate dihydrochalcones, α-benzyl-α′- alkyl acetones, dihydrocinnamaldehydes, and α-benzyl β-keto esters (from Baylis-Hillman adducts). A practical multigram synthesis of an intermediate for Propafenone was also demonstrated. Copyright
Synthesis, complexation behavior and application of a new diphosphite ligand in rhodium-catalyzed hydroformylation
Mikhel, Igor S.,Dubrovina, Natalia V.,Shuklov, Ivan A.,Baumann, Wolfgang,Selent, Detlef,Jiao, Haijun,Christiansen, Andrea,Franke, Robert,Boerner, Armin
experimental part, p. 3050 - 3057 (2011/09/20)
Oxidative coupling of 3-(3-tert-butyl-4-hydroxyphenyl)propionic acid methyl ester (2) gave dimethyl 3,3′-(5,5′-di-tert-butyl-6,6′- dihydroxybiphenyl-3,3′-diyl)-dipropionate (1c), which upon phosphorylation/transesterification with a phosphochloridite derived from (R)-binaphthol, formed the new unsymmetrical binaphthol-bridged diphosphite 4. A rhodium catalyst based on 4 as ligand gave predominantly iso-selectivity in the hydroformylation of selected styrenes but opposite regioselectivity with 2,6-disubstituted derivatives. New chelate metal complexes (acac)RhL, PdCl 2L and PtCl2L have been synthesized by reacting 4 with (acac)Rh(CO)2, PdCl2(MeCN)2 and PtCl 2(COD), respectively. The structure of obtained compounds is determined based on 1H, 13C, 31P and 195Pt NMR spectroscopy and mass spectrometry data.
Efficient platinum(II) catalyzed hydroformylation reaction in water: Unusual product distribution in micellar media
Gottardo, Marina,Scarso, Alessandro,Paganelli, Stefano,Strukul, Giorgio
experimental part, p. 2251 - 2262 (2010/12/25)
The hydroformylation of a variety of terminal and internal alkenes is efficiently performed by cationic platinum triflate complexes of the type [P2Pt(H2O)2](OTf)2 under mild conditions in an aqueous micellar medium. The use of surfactants is essential to ensure dissolution of the catalyst and substrate in water with catalysts being positioned on the anionic surface of the micelles. Aldehydes are obtained with linear to branched ratios up to >99:1. With styrene derivatives also the corresponding benzaldehydes are formed. The catalyst can be separated by extraction of the organic products with hexane and recycled for at least four times with only a modest loss of activity and no effect on selectivity.
Highly regioselective hydroformylation of Styrene and its derivatives catalyzed by Rh complex with tetraphosphorus ligands
Yu, Shichao,Chie, Yu-Ming,Guan, Zheng-Hui,Zou, Yaping,Li, Wei,Zhang, Xumu
supporting information; experimental part, p. 241 - 244 (2009/06/28)
Styrene has been hydroformylated to the linear aldehyde with surprisingly high regioselectivity (l/b up to 22 for styrene) by using Rh complex with tetraphosphorus ligand. To the best of our knowledge, this is the highest linear regioselectivity reported for the hydroformylation of styrene and its derivatives. This protocol is in sharp contrast to other processes that favor producing branched aldehyde (typically >95% branched for most bidentate systems).
