147228-21-5Relevant articles and documents
Asymmetric synthesis of 1,3-oxazolidines via intramolecular aza-michael addition by bifunctional organocatalysts
Fukata, Yukihiro,Asano, Keisuke,Matsubara, Seijiro
supporting information, p. 355 - 357 (2013/05/09)
A novel synthetic route to optically active 1,3-oxazolidines via formal [3 + 2] cycloaddition in the presence of cinchonaalkaloid- thiourea-based bifunctional organocatalysts is reported. This protocol gives easy access to a wide range of chiral 1,3- oxazolidines. In addition, the results show that bifunctional organocatalysts can effect the intramolecular aza-Michael addition, leading to the asymmetric synthesis of nitrogencontaining heterocycles.
Total syntheses of the spermine alkaloids (-)-(R,R)-hopromine and (±)-homaline
Ensch, Corinne,Hesse, Manfred
, p. 1659 - 1673 (2007/10/03)
The diastereoselective synthesis of the spermine alkaloid (R,R)-hopromine (2) is described. The as yet unknown absolute configuration of naturally occurring (-)-hopromine (2) is (R,R) and was established by comparison of the reported specific rotation of the natural product with that of the synthetic one. Preparation of the characteristic bis-8-membered lactam scaffold was carried out by convergent build-up of basic chiral azalactam units 21a and 21b and subsequent iterative linking (Schemes 5 and 6). Key steps in the analogous syntheses of 4-alkyl-hexahydro-1,5-diazocin-2(1H)-ones 21a and 21b were the introduction of the unbranched alkyl side chains into their common precursor 14 via cuprate reaction and the Sb(OEt)3-assisted cyclization of the open-chain intermediates 20a and 20b, respectively (Schemes 3 and 4). The chiral iodoester 14 was prepared from commercially available (+)-L-aspartic acid (12). Based on the synthetic strategy developed for (R,R)-hopromine (2), a rapid access to the parent alkaloid homaline (1) in its (±)-form is given.
An enantiospecific synthesis of β-amino acids
Jefford,Wang
, p. 1111 - 1114 (2007/10/02)
L-Aspartic acid by regioselective modification of the α-carboxylic acid group, namely N-tosylation, anhydride formation, reduction, iodo-esterification, alkylation, and deprotection afforded a series of γ-alkyl β-aminobutyric acids of the R configuration (ee > 99%).
