Titanium-mediated fragment union processes in complex molecule synthesis: Development of a branched reaction pathway of high step economy for the synthesis of complex and diverse polyketides

We describe a synthetic pathway to structurally complex and diverse polyketides based, in part, on regio- and stereoselective titanium-mediated coupling reactions. The sequences described allow for rapid assembly of polyketide-inspired architecture while providing significant flexibility for the establishment of diverse stereochemical relationships and substitution patterns along the carbon backbone (including stereodefined alkenes and 1,3-dienes, saturated and unsaturated lactones, hemiketals, α,β-unsaturated carbonyls, and spiroketals).