Abstract
Vinylic iodides were identified as useful intermediates for the synthesis of the C17-C27 fragment of the bryostatins with control of the geometry of the exocyclic methoxycarbonylmethylene group. Following literature precedent, the Piers (E)-stereoselective addition of tributyltin hydride to an alkynoate followed by ester reduction and tin-iodine exchange gave vinylic iodides that could be used to form the C20-C21 bond of the bryostatins. Chelation controlled addition of lithiated 3-silyloxypropynes to 2-alkoxyaldehydes followed by reductive iodination was used to prepare vinylic iodides that could be used in the complementary assembly of the C21-C22 bond of the bryostatins. Initial studies of the synthesis of intermediates for metathesis studies using metal catalysed reactions of a vinylic iodide for C21-C22 bond formation were complicated by cyclisation reactions.
Original language | English |
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Pages (from-to) | 3316-3328 |
Number of pages | 13 |
Journal | Tetrahedron |
Volume | 73 |
Issue number | 24 |
Early online date | 22 Apr 2017 |
DOIs | |
Publication status | Published - 15 Jun 2017 |
Keywords
- Chelation control
- Conjugate addition
- Stereoselective synthesis
- Tin-iodine exchange
- Vinylic iodides