Mechanistic analysis of the photocycloaddition of silyl-tethered alkenes.
The photochemistry of substituted cinnamyloxy silanes has been examined in both cyclohexane and acetonitrile solvents. Alkene isomerization occurs in addition to cycloaddition. Fluorescence quantum yields and excited singlet state lifetimes have been determined for each compound. We have used the information in order to better understand the regio- and stereoselectivity of photocycloaddition between silyl-tethered cinnamyl groups. This study allows us to conclude that the 2 + 2 photocycloaddition between alkenes is not a Woodward-Hoffmann orbital symmetry controlled event. The most consistent explanation for the excellent regio- and stereoselectivity is that the photocycloaddition is conformationally controlled.
Fleming
Steven A
SA
Department of Chemistry & Biochemistry, Brigham Young University, Provo, UT 84602, USA. steve_fleming@byu.edu
Parent
Alexander A
AA
Parent
Ephraim E
EE
Pincock
James A
JA
Renault
Lise
L
D000438:Alcohols / Q000138:chemical synthesis / Q000737:chemistry / Q000528:radiation effects; D000475:Alkenes / Q000737:chemistry* / Q000528:radiation effects; D003500:Cyclization; D015394:Molecular Structure; D010777:Photochemistry; D012821:Silanes / Q000138:chemical synthesis / Q000737:chemistry* / Q000528:radiation effects; D013237:Stereoisomerism; D014466:Ultraviolet Rays
D000438:Alcohols; D000475:Alkenes; D012821:Silanes