In this work, we target new methods to prepare the cyclobutene carbon scaffold, a structural feature found in both natural and non-natural products. It has long been known that cyclobutanes can be synthesized with through [2 + 2] cycloadditions promoted by ultraviolet (UV) light; however, UV light sources are expensive, hazardous to use, and often lead to undesired reactivity.  To avoid the challenges of using high energy, UV light, our reactions were carried out under lower energy visible light (blue LEDs). In this project, we report cyclobutane syntheses with vinylogous esters/vinylogous amides and enones, in the presence of iridium transition metal catalysts. Examples result in modest yields and excellent regio- and diastereoselectivity. The substrate scope was investigated to probe how structural modifications impact both reactivity and selectivity of the photocycloaddition.  In an effort to understand the mechanism by which these reactions proceed, photophysical properties: phosphorescence and absorbance, of the substrates and catalysts, are reported.

Carbon-carbon bond formation by visible light photocatalysis: [2 + 2] photocycloadditions of vinylogous esters and amides

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.