Enantioselective synthesis of (S)- and (R)-α-methylserines: application to the synthesis of (S)- and (R)-N-Boc-N,O-isopropylidene-α-methylserinals
摘要:
This report describes the synthesis of enantiomerically pure (S)- and (R)-alpha -methylserines on a multigram scale, starting from the Weinreb amide of 2-methyl-2-propenoic acid and using a stereodivergent synthetic route that involves a Sharpless asymmetric dihydroxylation reaction. As a synthetic application of these quaternary alpha -amino acids, they were used as starting materials in the synthesis of the well-known valuable homochiral (S)- and (R)-N-Boc-N,O-isopropylidene-alpha -methylserinal building blocks. (C) 2001 Elsevier Science Ltd. All rights reserved.
An alternative approach to (S)- and (R)-2-methylglycidol O-benzyl ether derivatives
作者:Alberto Avenoza、Carlos Cativiela、Jesús M. Peregrina、David Sucunza、Marı́a M. Zurbano
DOI:10.1016/s0957-4166(01)00230-0
日期:2001.6
This report describes the gram scale synthesis of (S)- and (R)-2,2,4-trimethyl-4-(hydroxymethyl)-1,3-dioxolanes using the Sharpless asymmetric dihydroxylation (AD) of the Weinreb amide of 2-methyl-2-propenoic acid. The 2-methylglycerol acetonides resultant from protection of the AD products were used as starting materials in the synthesis of O-benzyl ethers of the valuable C4-chiral building blocks (S)- and (X)-2-methylglycidol. (C) 2001 Elsevier Science Ltd. All rights reserved.
Preparation of 2(R) and 2(S) methyl-2-methylglycerates
作者:Juan B. Rodríguez、Sanford P. Markey、Herman Ziffer
DOI:10.1016/s0957-4166(00)86020-6
日期:1993.1
Optically pure samples of both enantiomers of methyl 2,3-dihydroxy-2-methylpropanoate were prepared by a chromatographic separation of their (-)-menthyl esters followed by hydrolysis and methylation. Their absolute stereochemistries were established by conversion into their 3-0-acetyl derivatives, compounds of established configuration. NMR and CG-MS methods of determining the optical purities of the diols are described.
Asymmetric synthesis of 2-alkyl-2,3-dihydroxypropionates from glycerol
作者:Kuang-Fu Yen、Biing-Jiun Uang
DOI:10.1016/s0957-4166(00)80504-2
日期:1992.6
The preparation of optically active 2-substituted 2,3-dihydroxypropionates from glycerol is described.
Enantioselective synthesis of (S)- and (R)-α-methylserines: application to the synthesis of (S)- and (R)-N-Boc-N,O-isopropylidene-α-methylserinals
作者:Alberto Avenoza、Carlos Cativiela、Francisco Corzana、Jesús M. Peregrina、David Sucunza、Marı́a M. Zurbano
DOI:10.1016/s0957-4166(01)00159-8
日期:2001.4
This report describes the synthesis of enantiomerically pure (S)- and (R)-alpha -methylserines on a multigram scale, starting from the Weinreb amide of 2-methyl-2-propenoic acid and using a stereodivergent synthetic route that involves a Sharpless asymmetric dihydroxylation reaction. As a synthetic application of these quaternary alpha -amino acids, they were used as starting materials in the synthesis of the well-known valuable homochiral (S)- and (R)-N-Boc-N,O-isopropylidene-alpha -methylserinal building blocks. (C) 2001 Elsevier Science Ltd. All rights reserved.
Asymmetric Dihydroxylation of Esters and Amides of Methacrylic, Tiglic, and Angelic Acid: No Exception to the Sharpless Mnemonic!
作者:Fabian Weber、Reinhard Brückner
DOI:10.1002/ejoc.201403622
日期:2015.4
are contradictory and partly in conflict with the Sharpless mnemonic. We systematically screened the SAD of esters and amides of angelic, tiglic, and methacrylic acid. Enantiocontrol arose in 14 of the 15 reactions, culminating at 99 % ee for the Weinreb amide of tiglicacid. The absolute configurations of all the nonracemic products were established by (stereo)chemical correlations. Without exception