Cycloadditions of Epoxy And Aziridinyl Enolsilanes

Abstract

The vast majority of natural products, bioactive molecules and drugs possess rings. Methodologies to assemble these structures bearing functional groups that facilitate further transformations are needed, and synthetic routes towards such natural products are often built around the key reactions that provide access to the rings.[1,2] Our group has been working on the cycloadditions, particularly intramolecular cycloadditions, that employ epoxy or aziridinyl enolsilanes as dienophiles. Governed by the stereochemistry of the oxirane or aziridine, these reactions ultimately contribute stereo-defined 1,3-hydroxy or 1,3-aminocarbonyl motifs to provide seven-membered cycloadducts.3 We have applied this reaction towards the synthesis of cortistatin A,4 and himandrine.5 We have also found that epoxy or aziridinyl enolsilanes react as enophiles in (3+2) cycloadditions with acyclic dienes and olefins.[6] In this presentation, we will report the latest developments of the reactions of these epoxy and aziridinyl enolsilanes, as well as our efforts towards applying these cycloadditions to the synthesis of natural products.