ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Diastereoselective syntheses
Diastereoselective syntheses O 0031Regio-and Diastereoselective Synthesis of 5-trans-Substituted and 5,5-Disubstituted 2-Pyrrolidinones Derived from (S)-Malic Acid. -The addition of preformed organo-cerium compounds, derived in situ from MeLi or BuLi and CeCl 3 to malic acid derivatives (I) and the transformation of the resulting 5-hydroxy quaternary lactams, obtained with complete or high regioselectivity into N-acyliminium ions, followed by addition of Et 3 SiH, allyltributyltin, or TmsCN, affords the title compounds mainly or exclusively as trans-diastereomers. Reactions of malic acid derivatives (I), performed in the first step with organolithium compounds (VII) or (XV) using DMPU as co-solvent, proceed in an analogous manner but with loss of the O-Pmb group for the reaction of lithium compound (VII). To establish the stereochemistry of product (VIII), it is converted into the known non-natural amino acid trans-4-hydroxy-D-proline. -(SCHUCH, C. M.; PILLI*, R. A.; Tetrahedron: Asymmetry 13 (2002) 18, 1973-1980; Inst. Quim., Univ. Estadual Campinas, 13083 Campinas, Sao Paulo, Brazil; Eng.) -Klein 07-033 2002 Diastereoselective syntheses
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.