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Synthesis of a C n –C n +6 Building Block Common to Important Polyol,Polyene Antibiotics from a Divinylcarbinol by a Desymmetrizing Sharpless Epoxidation
Author(s) -
Nachbauer Luc,
Brückner Reinhard
Publication year - 2013
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201300181
Subject(s) - chemistry , epoxide , wittig reaction , polyene , stereochemistry , polyol , ether , alkyl , chemical synthesis , medicinal chemistry , organic chemistry , catalysis , biochemistry , in vitro , polyurethane
A stereocontrolled synthesis of the enantiomerically pure epoxide 7b from propargyl ether 15 has been realized in 15 steps. Epoxide 7b represents a building block for the “eastern” moieties of the title compounds. Key steps in our approach were a desymmetrizing Sharpless epoxidation (→ anti , cis ‐ 16 ), the selective processing of the bis‐enolate of the bis( tert ‐butyl alkoxyacetate) 11 through a diastereoselective [2,3]‐Wittig rearrangement (→ syn , syn ‐ 9 ), and a stereo‐ and chemoselective iodolactonization (→ 35 ). The CO 2 H groups of dicarboxylic acid 37 were differentiated in a one‐pot bis‐oxidation reaction. The latter entailed the novel transformation of HO 2 CCH 2 ‐ O ‐alkyl into AcOCH 2 ‐ O ‐alkyl.