New Methodology to Prepare Polyfunctionalized Cycloheptane Synthons,with Four Stereocenters, by Hydrolytic Cleavage of the Oxygen Bridge in C1-functionalized 8-oxabicyclic [4+3]-cycloadducts

A new synthetic methodology to obtain polyfunctionalized cycloheptane synthons, with up to four stereocenters, is presented. Three key processes are involved in this methodology: first, the synthesis of C1-functionalized 8-oxabicyclo[3.2.1]oct-6-en-3-ones by a [4+3] cycloaddition reaction; second, the stereoselective reduction of the carbonyl group on C3 and third, the hydrolytic cleavage of the oxygen bridgeof the cycloadducts. This synthetic methodology is versatile enough to allow the preparation of a wide varietyof polypropionate synthetic building blocks.