Control of the Intramolecular [2+2] Photocycloaddition in a Bis-Stilbene Macrocycle
作者:Yuewen Xu、Mark D. Smith、Jeanette A. Krause、Linda S. Shimizu
DOI:10.1021/jo900443e
日期:2009.7.3
protecting groups. Upon UV-irradiation in both the solid state and DMSO solution, the free urea macrocycle undergoes a cis−transphotoisomerization that is followed by a [2+2] cycloaddition to afford a single product in high yield. The presence of the triazinanone urea protecting groups does not alter the cis−transphotoisomerization but greatly decreases the selectivity of the photocycloaddition step