13175-76-3Relevant academic research and scientific papers
Stereocontrol in the synthesis of cyclic amino acids: a new ligand for directed hydrogenation through hydrogen bonding
Gandi, Vasudeva Rao,Doan, Bao Nguyen Do,Kasinathan, Sivarajan,Bates, Roderick W.
, p. 2753 - 2758 (2019)
A system for the directed hydrogenation of nitrogen heterocycles is described in which hydrogen is delivered cis to a hydroxymethyl group by a rhodium catalyst with a simple phosphine ligand. The chemistry is applied to the synthesis of the hygric acid moiety of lincomycin and the pipecolic acid moiety of Argatroban. A series of control experiments indicate that the stereoselectivity is a result of a combination of both coordination and hydrogen bonding.
Chelate and trans effect of P,O donor phosphine ligands on rhodium catalyzed carbonylation of methanol
Dutta, Dipak Kumar,Deb, Biswajit,Hua, Guoxiong,Woollins, J. Derek
experimental part, p. 7 - 12 (2012/03/09)
Four complexes of the type [Rh(CO)Cl(η2-P,O-L)](1a,1b) and [Rh(CO)Cl(η1-P-L)2](2a,2b), where L = Ph 2PC6H4-2-OCH3(a) and Ph 2PC6H4-2-CH2OCH3(b), have been synthesized by the reaction of [Rh(CO)2Cl]2 with appropriate mol equivalents of the ligands in CH2Cl2. The complexes show single intense ν(CO) bands in the range 1965-1989 cm -1 indicating the presence of terminal carbonyl groups. All the complexes have been characterized by elemental analyses, mass spectrometry, IR and multinuclear NMR (1H, 31P and 13C) spectroscopy, and the molecular structure of the ligand b is determined by single crystal X-ray diffraction. The complexes undergo oxidative addition (OA) with excess CH3I to afford Rh(III)-acyl complexes of the type [RhCl(COCH3)I(L)](3a,3b) and [RhCl(COCH3)I(L) 2](4a,4b). The kinetic data for the OA reactions with CH3I indicate a first order reaction and also exhibit that the rate of OA for the chelate complexes (1a and 1b) is higher than those of trans-complexes (2a and 2b). The catalytic efficiencies of 1a, 1b, 2a and 2b in carbonylation of methanol exhibit higher Turn Over Frequency (TOF) 689-1808 h-1 than the well-known Monsanto's species [Rh(CO)2I2]- (TOF = 464-1000 h-1) under similar experimental conditions. The catalytic activities vary in the order as 1a > 1b > 2a > 2b.
