Expedient and Diastereodivergent Assembly of Terpenoid Decalin Subunits having Quaternary Stereocenters through Organocatalytic Robinson Annulation of Nazarov Reagent
report an expedient approach to highly functionalized cis‐ and trans‐decalines that could function as key structural subunits toward the synthesis of various classes of terpenoids. Key to the strategy is an organocatalyzed Robinsonannulation reaction of the Nazarovreagent that affords chiral enone building blocks with high enantioselectivities. The quaternary carbon stereogenic center can direct the subsequent
diastereoselectivity in a bakers’ yeastreduction of various alkyl 2-alkyl-3-oxoalkanoates can be controlled by a thermal treatment of the yeast in the presence of methyl vinyl ketone. Pretreated bakers’ yeast gives the corresponding (2R,3S)-hydroxy esters selectively. Two β-keto ester reductases, named L-enzyme-1 and L-enzyme-2, are actual reductants of intact bakers’ yeastreduction. The thermal stability
Diastereoselective and diastereoconvergent syntheses of 2- and 3-substituted morpholine congeners are reported. Starting from tosyl-oxazatedine 1 and α-formyl carboxylates 2, base catalysis is utilized to yield morpholine hemiaminals. Their further synthetic elaborations allowed the concise constructions of conformationally rigid morpholines. The observed diastereoselectivities and the unusual diastereoconvergence
Structure–activity relationships of the peptide deformylase inhibitor BB-3497: modification of the methylene spacer and the P1′ side chain
作者:Stephen J. Davies、Andrew P. Ayscough、R.Paul Beckett、Ryan A. Bragg、John M. Clements、Sheila Doel、Christine Grew、Steven B. Launchbury、Gemma M. Perkins、Lisa M. Pratt、Helen K. Smith、Zoë M. Spavold、S.Wayne Thomas、Richard S. Todd、Mark Whittaker
DOI:10.1016/s0960-894x(03)00532-8
日期:2003.8
Structural modifications to the peptide deformylase inhibitor BB-3497 are described. In this paper, we describe the initial SAR around this lead for modifications to the methylene spacer and the P1' side chain. Enzyme inhibition and antibacterial activity data revealed that the optimum distance between the N-formyl hydroxylamine metal binding group and the P1' side chain is one unsubstituted methylene unit. Additionally, lipophilic P1' side chains that closely mimic the methionine residue in the substrate provided compounds with the best microbiological profile. (C) 2003 Elsevier Ltd. All rights reserved.
Synthesis of aldehydes from dihydro-1,3-oxazines
作者:A. I. Meyers、A. Nabeya、H. W. Adickes、I. R. Politzer、G. R. Malone、A. C. Kovelesky、R. L. Nolen、R. C. Portnoy