Regioselective silylation of 5-(2′-hydroxyethyl)cyclopent-2-en-1-ol and 6-(2′-hydroxyethyl)cyclohex-2-en-1-ol
作者:Hao Chen、Erika Plettner
DOI:10.1016/j.tetlet.2012.02.020
日期:2012.4
Herein we report regioselective and mild reactions for the tert-butyldimethylsilyl mono-protection of 5-(2′-hydroxyethyl)cyclopent-2-en-1-ol (2) and 6-(2′-hydroxyethyl)cycohex-2-en-1-ol (5) at the primaryhydroxyl group or at the secondary allylic hydroxyl group. The different steric environment surrounding the secondary allylic and saturated primaryalcohols is mainly invoked to rationalize the observed
Cyclization Reactions through DDQ-Mediated Vinyl Oxazolidinone Oxidation
作者:Lei Liu、Paul E. Floreancig
DOI:10.1021/ol901188q
日期:2009.7.16
Vinyl oxazolidinones react with DDQ to form alpha,beta-unsaturated acyliminium ions in a new method for forming electrophiles under oxidative conditions. Appended nucleophiles undergo 1,4-addition reactions with these intermediates to form cyclic vinyl oxazolidinones with good levels of diastereocontrol, highlighting a new approach to utilizing oxidative carbon-hydrogen bond functionalization to increase molecular complexity.
Novel stereoselective synthesis of spiroketal structure using Pd(II)-catalyst
We report a highly stereoselective palladium(II)-catalyzed intramolecular cyclization of 1,11-dihydroxyundec-9-en-5-one derivatives via unstable hemiacetal intermediates, in which cyclization occurs without activation of the allylic alcohol to afford spiroketal structures. (C) 2013 Elsevier Ltd. All rights reserved.