A Flexible Synthesis of Polypropionates via Diastereodivergent Reductive Ring-Opening of Trisubstituted Secondary Glycidols.

Polypropionates, characterized by their alternating sequence of stereocenters bearing methyl- and hydroxy-groups, are structurally diverse natural products of utmost importance. [1] Herein, we introduce a novel concept approach towards polypropionate synthesis featuring a diastereodivergent reductive epoxide-opening as a key step. Readily available and stereochemically uniform trisubstituted sec-glycidols serve as branching points for the highly selective synthesis of all isomers of polypropionate building blocks with three or more consecutive stereocenters. Stereodiversification is accomplished by an unprecedented mechanism-control over the stereochemically complementary modification of the epoxide's tertiary C-atom with excellent control of regio- and stereoselectivity. Since our method is not only suited for the preparation of specific targets but also for compound libraries, it will have a great impact on polypropionate synthesis.