Turks, MarisFairweather, Kelly A.Scopelliti, RosarioVogel, Pierre2011-12-162011-12-162011-12-16201110.1002/ejoc.201100196https://infoscience.epfl.ch/handle/20.500.14299/73967WOS:000291583700007The 2,3-anti-3,4-syn-stereotriad (1Z,2S,3R,4S)-1-ethylidene-2,4-dimethyl-3-[(1S)-1-phenylethoxy]-5-oxopent-1-yl isobutyrate {(-)-8, obtained in a one-pot operation from the trimethylsilyl (Z)-enol ether derived from pentan-3-one and (1E,3Z)-1[(1S)-phenylethoxy]-2-methylpenta-1,3-dien-3-yl isobutyrate through SO2 umpolung} contains an ethyl ketone moiety that undergoes diastereoselective cross-aldol reactions with acetaldehyde. After subsequent reductions, various diastereomeric stereohexads (polypropionate fragments containing six contiguous stereogenic centres) in which the (Z)-enol isobutyrate units remained intact were obtained. After suitable protection, these were converted into their corresponding lithium (Z)-enolates, which could react with isopropylidene D-glyceraldehyde [(+)-9] to give aldol products that were reduced to various stereodecads (polyketides with ten contiguous stereogenic centres). The disclosed chemistry represents a quick, asymmetric, diastereoselective and stereodivergent construction of long-chain polyketides and analogues by a double-chain-elongation strategy.Aldol reactionsAldol reductionPolyketidesPolypropionatesUmpolungBeta-Hydroxy KetonesHypervalent Iodine ReagentsAldol Addition-ReactionsStereoselective-SynthesisPolypropionate SynthesisNatural-ProductsSulfur-DioxideMethyl KetonesDiastereoselective ReductionConfigurational Assignmenttext::journal::journal article::research article