Preparation of enantiopure 3,5,5-trialkyl-γ-butyrolactones by diastereospecific 5-endo halo lactonizations
摘要:
A new preparation of 3,5,5-trialkyl-gamma-butyrolactones of defined absolute configuration is reported. This method involves the diastereoselective alkylation of 3,4-ethylenic acids after incorporation of a chiral Evans auxiliary, and then after separation of the two diastereomers and hydrolysis of the auxiliary, stereospecific halo lactonizations. This method was applied to the preparation of a natural product, present in a sponge. (c) 2007 Elsevier Ltd. All rights reserved.
Efficient Pd-Catalyzed Regio- and Stereoselective Carboxylation of Allylic Alcohols with Formic Acid
作者:Ming-Chen Fu、Rui Shang、Wan-Min Cheng、Yao Fu
DOI:10.1002/chem.201701971
日期:2017.7.3
Formic acid is efficiently used as a C1 source to directly carboxylate allylicalcohols in the presence of a low loading of palladium catalyst and acetic anhydride as additive to afford β,γ‐unsaturated carboxylic acids with excellent chemo‐, regio‐, and stereoselectivity. The reaction proceeds through a carbonylation process with in situ‐generated carbon monoxide under mild conditions, avoiding the
Benzyl esters and thiolesters of 4-aryl-3-butenoic acids, intermediates therefor, synthesis thereof, and the use of said esters and thiolesters for the control of pests.
An Approach to Enantioselective 5-endo Halo-Lactonization Reactions
作者:Jean Marc Garnier、Sylvie Robin、Gérard Rousseau
DOI:10.1002/ejoc.200700041
日期:2007.7
Enantioselective lactonization of 4-substituted but-3-enoic acids using iodobis(N-methylephedrine) hexafluoroantimonate in dichloromethane at low temperatures is reported. The presence of bis(N-methylephedrine)silver(I) hexafluoroantimonate, derived from the excess amounts of N-methylephedrine and silver hexafluoroantimonate that were necessary for the generation of the iodo complex in the reaction
[EN] BETA-TETRAZOLYL-PROPIONIC ACIDS AS METALLO-BETA-LACTAMASE INHIBITORS<br/>[FR] ACIDES BÊTA-TÉTRAZOLYLE-PROPIONIQUES UTILES EN TANT QU'INHIBITEURS DES MÉTALLO-BÊTA-LACTAMASES
申请人:MERCK SHARP & DOHME
公开号:WO2015171474A1
公开(公告)日:2015-11-12
The present invention relates to compounds of formula I that are metallo-β-lactamase inhibitors, the synthesis of such compounds, and the use of such compounds for use with β-lactam antibiotics for overcoming resistance.
A direct carbonylation of allylic alcohols has been realized for the first time with highcatalyst activity at low pressure of CO (10 bar). The procedure is described in detail for the carbonylation of E-nerolidol, an important step in a new BASF-route to (−)-ambrox. Key to high activities in the allylic alcohol carbonylation is the finding that catalytic amounts of carboxylic anhydride activate the