Synthesis of a spiroacetal intermediate for the synthesis of the anti-Helicobacter pylori agent CJ-12, 954

Show simple item record Brimble, MA en Funnell, CJ en Gorsuch, S en Sidford, M en 2011-09-19T22:06:08Z en 2001 en
dc.identifier.citation Arkivoc 2001(1):74-87 2001 en
dc.identifier.issn 1424-6376 en
dc.identifier.uri en
dc.description.abstract A method has been established for the synthesis of the 5,5-spiroacetal moiety of the anti-Helicobacter pylori agents CJ-12,954 1 and CJ-13,014 2 in racemic form and as a mixture of stereoisomers. Retrosynthetically the key spiroacetal 9 is derived from the acyclic protected dihydroxyketone precursor 10 or 11 which in turn are available from enynone 25 or 26. Enynones 25 and 26 were prepared via addition of the acetylide derived from acetylenes 13 or 14 to aldehyde 12 followed by oxidation of the resultant alcohols 23 and 24 respectively. Acetylenes 13 and 14 in turn were available via [2,3]-sigmatropic rearrangement of allyl propargyl ether 16. Extension of this reaction in an asymmetric sense by use of a chiral base would have provided acetylene 14 in enantioenriched form, however, efforts towards this end were disappointing. Enynones 25 and 26 were converted to keto epoxides 10 and 11 respectively by treatment with meta-chloroperbenzoic acid followed by hydrogenation of the acetylene. Attempts to effect deprotection and cyclization of bis-silyl ethers 10 and 11 to spiroacetal 9 were complicated by the presence of the epoxide. In an alternative approach enynone 26 was converted to methyl acetal 29 upon treatment with camphorsulfonic acid in methanol. Subsequent epoxidation of the terminal alkene 29 afforded epoxide 30 which then underwent smooth hydrogenation and cyclization in situ to the desired spiroacetal 9. en
dc.relation.ispartofseries Arkivoc en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights.uri en
dc.title Synthesis of a spiroacetal intermediate for the synthesis of the anti-Helicobacter pylori agent CJ-12, 954 en
dc.type Journal Article en
pubs.issue 1 en
pubs.begin-page 74 en
pubs.volume 2001 en
dc.rights.holder Copyright: ARKAT USA, Inc en
pubs.end-page 87 en
dc.rights.accessrights en
pubs.subtype Article en
pubs.elements-id 139350 en Science en Chemistry en Science Research en Maurice Wilkins Centre (2010-2014) en
pubs.record-created-at-source-date 2013-06-05 en

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