A diastereoselective and enantioselective synthesis of (Z)-1-benzoylamino-2-tritylsulfanylcyclopropanecarboxylic acid derivatives 8a,b and 9a,b was achieved starting from (-)- or (+)-menthyl 2-benzoylamino-3-tritylsulfanylacrylates 3a,b. Compounds 3 were reacted with diazomethane giving the corresponding pyrazolines 4a,b and 5a,b. These compounds, on melting, were transformed, under steric control, into the cyclopropaneamino acid derivatives (R,R)-8a,b and (S,S)-9a,b. The synthesis of a large class of chiral 2-S-alkyl-1-aminocyclopropanecarboxylic acid derivatives is possible after removing the trityl protecting group and subsequent alkylation reactions. © 2001 Elsevier Science Ltd. All rights reserved.
Masked constrained cysteines: Diastereoselective and enantioselective synthesis of 1-amino-2-mercaptocyclopropanecarboxylic acid derivatives / F. Clerici, M.L. Gelmi, D. Pocar, T. Pilati. - In: TETRAHEDRON-ASYMMETRY. - ISSN 0957-4166. - 12:19(2001), pp. 2663-2669. [10.1016/S0957-4166(01)00466-9]
Masked constrained cysteines: Diastereoselective and enantioselective synthesis of 1-amino-2-mercaptocyclopropanecarboxylic acid derivatives
F. ClericiPrimo
;M.L. GelmiSecondo
;D. PocarPenultimo
;
2001
Abstract
A diastereoselective and enantioselective synthesis of (Z)-1-benzoylamino-2-tritylsulfanylcyclopropanecarboxylic acid derivatives 8a,b and 9a,b was achieved starting from (-)- or (+)-menthyl 2-benzoylamino-3-tritylsulfanylacrylates 3a,b. Compounds 3 were reacted with diazomethane giving the corresponding pyrazolines 4a,b and 5a,b. These compounds, on melting, were transformed, under steric control, into the cyclopropaneamino acid derivatives (R,R)-8a,b and (S,S)-9a,b. The synthesis of a large class of chiral 2-S-alkyl-1-aminocyclopropanecarboxylic acid derivatives is possible after removing the trityl protecting group and subsequent alkylation reactions. © 2001 Elsevier Science Ltd. All rights reserved.Pubblicazioni consigliate
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