Homochiral Diels-Alder adduct of 2,4-dimethylfuran to 1-cyanovinyl (1'R)- or (1'S)-camphanate are transformed readily into polypropionate fragments containing four or five contiguous stereogenic centres. They can be condensed via cross-aldolizations to lithium enolates of 7-oxabicyclo[2.2.1]heptan-2-ones with high diastereoselectivity generating long-chain systems containing up to eleven stereogenic centres and tertiary alcoholic moieties.