Monoterpenos di-hidroxilados e hidróxi-nitrogenados 1,2 e 1,3 como ligantes quirais em reação de reformatsky assimétrica 1,2- and 1,3-dihydroxylated and hydroxynitrogenated monoterpenes as chiral ligands in the asymmetric reformatsky reaction

Autor: Carlos Magno R. Ribeiro, Cristina M. Morita, Mônica P. Maia
Jazyk: English<br />Spanish; Castilian<br />Portuguese
Rok vydání: 2008
Předmět:
Zdroj: Química Nova, Vol 31, Iss 4, Pp 735-739 (2008)
Druh dokumentu: article
ISSN: 0100-4042
1678-7064
DOI: 10.1590/S0100-40422008000400004
Popis: This study describes the use of three (-)-alpha-pinene derivatives, one diol-1,2 [(-)-(1R, 2R, 3S, 5R)-2,6,6-trimethylbicyclo[3.1.1]heptane-2,3-diol 4] and two piridine-hydroxy derivatives [(+)-(1R,2S,3R,5S)-2,6,6-trimethyl-3-(2-pyridinylmethyl)bicyclo[3.1.1]heptan-3-ol 7 and (-)-(1R,2S,3R,5S)-2,6,6-trimethyl-3-[2-(2-pyridinyl) ethyl]bicyclo[3.1.1]heptan-3-ol 8]; one diol-1,3 [(-)-(1S,2R,5S)-2-(1-hydroxy-1-methylethyl)-5-methylcyclohexanol 5] derived from (+)-isopulegol 2 and one diol-1,3 [(+)-(1R,2R,5R)-2-(1-hydroxy-1-methylethyl)-5-methylcyclohexanol 6] derived from (+)-neo-isopulegol 3, as ligands in the asymmetric Reformatsky reaction. The best enantiomeric excess of beta-hydroxy ester obtained in the Reformatsky asymmetric reaction was 18% using ligand 6, and the chemical yield of the reactions was 65% on average.
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