Enantioselective Syntheses of Colletodiol, Colletol, and Grahamimycin A
摘要:
[GRAPHICS]The enantioselective synthesis of colletodiol has been achieved in 11 steps from methyl 1,3,5-octatrienoate and 16 total steps from both ethyl sorbate and methyl 1,3,5-octatrienoate. The route relies upon an enantio- and regioselective Sharpless dihydroxylation and a palladium-catalyzed reduction to form a 5-hydroxy-1-enoate and an 7-hydroxy-1,3-dienoate. These esters were further functionalized, coupled, and macrolactonized to provide colletodiol after deprotection. Grahamimycin A and colletol were synthesized in one and two steps, respectively, from colletodiol.
An Enantioselective Synthesis of Tarchonanthuslactone
作者:Sarah D. Garaas、Thomas J. Hunter、George A. O'Doherty
DOI:10.1021/jo0163400
日期:2002.4.1
enantioselective synthesis of tarchonanthuslactone has been achieved in eight steps from ethyl sorbate. The asymmetry of the route was introduced via a Sharpless asymmetric dihydroxylation allowing access to either enantiomer. The synthesis utilizes a palladium-catalyzed reduction and a diastereoselective base-catalyzed acetal formation as the key steps. The pyran ring of tarchonanthuslactone was established
De novo asymmetric syntheses of C-4-substituted sugars via an iterative dihydroxylation strategy
作者:Md. Moinuddin Ahmed、George A. O’Doherty
DOI:10.1016/j.carres.2006.03.024
日期:2006.7
highly efficient route to various C-4 substitutedsugar lactones has been developed. The key to the overall transformation is the sequential osmium-catalyzed dihydroxylation reaction of substituted 2,4-dienoates and an allylic substitution at the C-4 position. When the Sharpless AD-mix procedure is used in a matched sense for the second dihydroxylation reaction, it results in an exceedingly diastereo-
An Enantioselective Synthesis of Benzylidene-Protected <i>syn</i>-3,5-Dihydroxy Carboxylate Esters via Osmium, Palladium, and Base Catalysis
作者:Thomas J. Hunter、George A. O'Doherty
DOI:10.1021/ol0156188
日期:2001.4.1
[GRAPHICS]The enantioselective syntheses of several protected syn-3,5-dihydroxy carboxylic esters have been achieved from the corresponding achiral 1,3-dieneoates, The route relies upon an enantio- and regioselective Sharpless dihydroxylation and a palladium-catalyzed reduction to form delta -hydroxy-1-enoates, The resulting delta -hydroxy-1-enoates are subsequently converted into benzylidene-protected 3,5-dihydroxy carboxylic esters in one step, The benzylidene-protected 3,5-dihydroxy carboxylic esters are produced in good overall yields (25% to 51%) and high enantiomeric excesses (80% to >95%).
A formal, stereoselective synthesis of the natural tetrahydropyran derivative ophiocerin D
作者:Julián Paños、Juan Murga、Eva Falomir、Miguel Carda、J. Alberto Marco
DOI:10.1016/j.tetasy.2010.01.013
日期:2010.3
A short, formal stereoselective synthesis of the naturally occurring tetrahydropyran derivative ophiocerin D is reported. The four stereocenters of the molecule were created with the aid of two Sharpless asymmetric dihydroxylations. (C) 2010 Elsevier Ltd. All rights reserved.