A concise protecting-group-free synthesis of cephalosporolides E and F
作者:Dipali A. Chaudhari、Pullaiah Kattanguru、Rodney A. Fernandes
DOI:10.1039/c5ra06991b
日期:——
A concise protecting-group-free synthesis of cephalosporolides E and F has been described. The key steps involve the one-pot conversion of L-mannonic-γ-lactone to γ-vinyl-β-hydroxy-γ-lactone, cross-metathesis and Wacker-type oxidative spiroketalization. The internal olefin served as a latent keto functionality with excellent delivery of a regioselective keto group for spiroketalization. The synthetic
A Common Synthetic Protocol for the Cyclic and Acyclic Core of Migrastatin, Isomigrastatin, and Dorrigocin via a Chiral β-Hydroxy-γ-butyrolactone Intermediate
作者:Narendar Reddy Gade、Javed Iqbal
DOI:10.1002/ejoc.201402830
日期:2014.10
A facile synthetic route has been developed for the synthesis of the cyclic and acycliccores of migrastatin, isomigrastatin, and dorrigocin. The commonsynthetic route goes via a β-hydroxy-γ-butyrolactoneintermediate that is obtained by a PdII-catalysed asymmetric allylic intramolecular cyclization of 3-hydroxy-2-methylhex-5-enoic acid following a protocol developed by White and coworkers.
Homochiral 4-hydroxy-5-hexenoic acids and their derivatives and homologues from carbohydrates
作者:Jie Song、Rawle I. Hollingsworth
DOI:10.1016/s0957-4166(01)00053-2
日期:2001.3
Efficient routes to chiral 4-hydroxy-5-hexenoic acids and lactones from D-gluconic acid-delta -lactone and L-mannonic acid-gamma -lactone are described. In this approach, the starting lactones are converted to 2,6-dibromo compounds that readily undergo zinc mediated elimination to generate the terminal alkene group in concert with 2-deoxygenation. The integrity of the remaining stereocenters is preserved during the reaction. The related important pharmaceutical intermediates (S)-3-hydroxy-4-pentenoic acid and (S)-1.3-dihydroxy-4-pentene were also prepared from 2-deoxyribose via the corresponding aldonolactone. (C) 2001 Elsevier Science Ltd. All rights reserved.