Diastereoselective and Enantioselective Intramolecular Amino−Zinc−Enolate Carbometalation Reactions. A New Polysubstituted Pyrrolidines Synthesis
作者:Edwige Lorthiois、Ilane Marek、Jean F. Normant
DOI:10.1021/jo970813e
日期:1998.4.1
The amino-zinc-enolate cyclization allowed a new and straightforward route to polysubstituted pyrrolidines from simple starting materials. From this study, we have been able to determine, for the first time, the stereochemical influence of the substituents on the ring in the carbocyclization reaction. The diastereoselectivity thus obtained was explained by a chairlike amino-zinc-enolate transition state.
Constraining the amide bond in N-Sulfonylated dipeptide VLA-4 antagonists
作者:Linda L. Chang、Ginger X. Yang、Ermengilda McCauley、Richard A. Mumford、John A. Schmidt、William K. Hagmann
DOI:10.1016/j.bmcl.2008.01.045
日期:2008.3
The integrin VLA-4 is implicated in several inflammatory disease states. In search of non-peptidic antagonists of VLA-4, rotational constraints were imposed on the amide bond of prototypical N-sulfonylated dipeptide VLA-4 antagonists. By judicious structural modi. cation of the side chains, trisubstituted imidazoles with moderate binding potencies were obtained, for example, 19, VLA-4 IC50 = 237 nM. (C) 2008 Elsevier Ltd. All rights reserved.
Synthesis of 2,3-disubstituted pyrrolidines by intramolecular addition of α-aminoalkyl radicals to electron deficient C C bonds
2,3-Disubstituted pyrrolidines are prepared by SmI2-pranoted cyclization of alpha-amino radicals generated from N-(alpha-benzotriazolylalkyl)alkenylamines containing a C=C bond activated by an electron withdrawing substituent. The diastereoselectivity of cyclization is moderate and depends on the nature of the substituent at the pyrrolidine 2-position. (C) 1999 Elsevier Science Ltd. All rights reserved.
(INDAZOL-4-YL)HEXAHYDROPYRROLOPYRROLONES AND METHOD OF USE