Cladosin C is one of the few known enaminotetramic acids, isolated from extracts of the deep sea fungus Cladosporium sphaerospermum. It was synthesised in ten steps and 14% overall yield by a late-stage amination of the corresponding 3-acyltetramic acid. This was obtained by a Dieckmann condensation of an N-β-ketoacylaminoester derived from dehydrovalinate and the thioester-terminated side chain containing
Synthesis of optically active chloro alkanoic esters
作者:Ugo Azzena、Giovanna Delogu、Giovanni Melloni、Oreste Piccolo
DOI:10.1016/s0040-4039(01)80743-7
日期:1989.1
The stereospecific synthesis (optical yield up to 94%) of opticallyactive (R)-alkyl-2-chloropropionate and (S)-alkyl-3-chlorobutanoate by the action of AlCl3 on the corresponding (S)-2-mesyloxy- and (R)-3-mesyloxy-derivatives is described.
通过AlCl 3对相应的(S)-2-mesyloxy-描述了(R)-3-甲磺酰氧基衍生物。
Carbonylation of alkyl sulfonates catalyzed by cobalt complexes
作者:Hisao Urata、Daisuke Goto、Takamasa Fuchikami
DOI:10.1016/0040-4039(91)80697-5
日期:1991.6
Alkylsulfonates (R1-OSO2R2) react with carbon monoxide and alcohol (R3-OH) in the presence of catalytic amounts of Co complex and Nal to afford the corresponding esters (R1-COOR3) in moderate to good yields.
Process for preparing optically active 3-azidocarboxylic acid derivatives and 3-aminocarboxylic acid derivatives
申请人:Bohm Andreas
公开号:US20070149794A1
公开(公告)日:2007-06-28
A process for enantioselectively preparing 3-azidocarboxylic acid derivatives comprises reacting 3-sulfonatocarboxylic acid derivatives with an alkali metal azide in a solvent selected from the group comprising certain carboxamides; a solvent mixture which comprises such carboxamides; a solvent mixture of water and a solvent miscible homogeneously with water; water with the proviso that the addition of a phase transfer catalyst is not used in the reaction in water; and DMSO. The resulting products are optionally reduced to 3-aminocarboxylic acid derivatives.
Efficient large scale stereoinversion of (R)-ethyl 3-hydroxybutyrate
作者:Andrew J. Carnell、Robert Head、Derek Bassett、Michael Schneider
DOI:10.1016/j.tetasy.2003.12.005
日期:2004.3
A three step method for the large scale preparation of enantiomerically pure ethyl (S)-3-hydroxybutyrate is reported starting from the commercial biopolymer poly[(R)-hydroxybutyrate]. The key step depends on the ability to cleanly invert the stereochemistry of (R)-ethyl 3-hydroxybutyrate via its mesylate ester under neutral conditions, avoiding the competing elimination process. This has been achieved in good (75%) yield on >100 g scale by controlled addition of the mesylate to a stirred slurry of calcium carbonate in water at 80 degreesC. (C) 2003 Elsevier Ltd. All rights reserved.