A silicon-centred tetrafunctionalised reagent for the cyclopropylmethylsilane-terminated prins reaction and a concise synthesis of lyngbic acid

A novel silicon-centred tetrafunctionalised reagent, tetra(2-ethenycylclopropylmethyl)silane. has been prepared as a mixture of all possible 19 diastereoisomers. It reacts with TMSOTf-activated acetals via initial Prins reaction of the olefin and 'termination' by the cyclopropylmethylsilane groups. In this manner it smoothly transfers three of its groups to form skipped diene ether products. The reaction is under stereoelectronic control and gives exclusively E-skipped dienes regardless of the initial cisltrans configuration of each of the reacting vinyl cyclopropanes, or the relative configurations of the other vinylcyclopropane groups in the silane. The synthetic utility of the reagent is demonstrated by its use in a concise Synthesis of marine natural product Lyngbic acid.