Photoinduced ring-opening olefination of cycloalkanols and access to tunable cycloenones

Abstract

We have developed a dual-catalytic strategy for the synthesis of linear alpha olefins with variable chain lengths from readily available cycloalkanols. This strategy was realized by combining photocatalyzed ring opening of cycloalkanols and Cu-mediated β-H elimination. The terminal desaturation was achieved at aryl and alkyl ketones’ γ , δ , ε , or more remote sites under mild conditions with remarkable functional group tolerance. The resulting diene products via this approach have the potential to be transformed into challenging tunable medium-sized cycloenones. • Wide functional group tolerance • Readily offer substrates for ring-closing metathesis • Access to tunable enones and cycloenones Alkenes are much preferred building blocks in organic synthesis. They are widely used in developing new reaction patterns and constructing sophisticated molecules. This inspires researchers to develop more alkene synthesis methodology from diverse substrates. Our methodology paved the way to preparation of terminal alkenes from cycloalkanols. Enones and cycloenones were thus achieved with variable chain lengths or ring sizes accordingly. As olefins are important building blocks, this transformation can serve as a powerful tool to enrich the arsenal of organic synthesis. Alcohols areall over the area of organic chemistry and the world. We contributed to the conversion of them into enones with at least one double bond. Enones with two double bonds could be perfectly employed in ring-closing metathesis, affording tunable cycloenones. It is interesting that if these cycloenones were converted into tertiary alcohols, they can be utilized in our methodology again.