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Synthesis of the 8‐Hydroxy Acid of Jasplakinolide
Author(s) -
Wattanasereekul Saengchai,
Maier Martin E.
Publication year - 2004
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200404004
Subject(s) - cyclopropanation , chemistry , alkene , stereocenter , cyclopropane , metathesis , allylic rearrangement , electrophile , depsipeptide , alkylation , stereochemistry , iodide , allyl alcohol , organic chemistry , medicinal chemistry , enantioselective synthesis , ring (chemistry) , catalysis , polymer , polymerization
The protected ω‐hydroxy acid 4b contained in the depsipeptide jasplakinolide ( 1 ) was prepared in a sequence of 13 steps from the silylated 3‐hydroxy ester 6 . By chain extension 6 was converted to the allyl alcohol 10 . A subsequent asymmetric cyclopropanation of the allylic alcohol 10 using the Charette method provided the hydroxymethylcyclopropane 12 with excellent diastereoselectivity. This cyclopropanation was used to establish the methyl‐bearing stereocenter at C‐6 of the hydroxy acid 4 by reductive ring cleavage of the (iodomethyl)cyclopropane 14 . The alkene 15 was used for a cross alkene metathesis reaction with 2‐methylacrylate 20 providing the enoate 19 . The derived allylic iodide 24 served as an electrophile in the final Evans alkylation step to give the ω‐hydroxy acid derivative 26 .