The Mannich Reaction of Malonates with Simple Imines Catalyzed by Bifunctional Cinchona Alkaloids: Enantioselective Synthesis of β-Amino Acids
作者:Jun Song、Yi Wang、Li Deng
DOI:10.1021/ja060716f
日期:2006.5.1
efficient, direct asymmetric Mannichreactions with malonates and N-Boc aryl and alkyl imines by cooperative hydrogen-bonding catalysis with a cinchona alkaloid bearing a thiourea functionality. We have also extended the scope of this reaction to beta-ketoesters. The synthetic value of this new reaction is demonstrated in the establishment of a convergent enantioselective route toward the biologically
Decarboxylative Aldol Reactions of Allyl β-Keto Esters via Heterobimetallic Catalysis
作者:Sha Lou、John A. Westbrook、Scott E. Schaus
DOI:10.1021/ja045981k
日期:2004.9.1
Mild and selective heterobimetallic-catalyzed decarboxylative aldol reactions involving allyl beta-keto esters have been developed. The reaction is promoted by Pd(0)- and Yb(III)-DIOP complexes at room temperature and involves the in situ formation of a ketoneenolate from allyl beta-keto esters followed by addition of the enolate to aldehydes. The reaction is a new example of heterobimetallic catalysis
Process for the preparation of carbapenem intermediates
申请人:Bayer Aktiengesellschaft
公开号:US04841042A1
公开(公告)日:1989-06-20
A process for the preparation of a 4-[3-carboxy-3-diazo-2-oxopropyl]azetidin-2-one of the formula ##STR1## comprising reacting a 4-acetoxy-2-azetininone of the formula ##STR2## with a compound of the formula ##STR3## in an inert solvent, in the presence of a base and of a silylating agent, in a one-pot process. Many of the products are new. The products are useful in the synthesis of carbapenem antibiotics.
An expeditious synthesis of a 1β-methylcarbapenem key intermediate
作者:Robert Deziel、Masaki Endo
DOI:10.1016/0040-4039(88)80016-9
日期:1988.1
The β-methylcarbapenem keyintermediate 4 was preparedvia a novel aldol-type alkylation of 2 with the divalent tin enolate 6 generatedin situ from 7 and metallic tin.
Stereoselective synthesis of 1-.beta.-alkyl carbapenem antibiotic
申请人:Bristol-Myers Company
公开号:US04841043A1
公开(公告)日:1989-06-20
There is disclosed a process for producing carbapenam diazo intermediates of the formula ##STR1## wherein R.sup.1 is hydrogen or a hydroxy-protecting group, R.sup.2 is a lower alkyl having from 1-6 carbon atoms, and R.sup.3 represents a conventional carboxyl-protecting group. The processs comprises alkylating a 4-substituted azetidinone with the tin enolate of an .alpha.-bromoketone, in the presence of a silver salt, iodine, or iodine salt as a catalyst, and a strongly polar solvent. The .beta./.alpha. yield of the product diazo intermediate is approximately 3/1.