Figure 1.
Substrate scope of the Lewis acid catalyzed intramolecular [2+2] photocycloaddition of coumarins (50 mol % 12, −75 °C, λ=366 nm).
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.