חיפוש מתקדם
Journal of Organic Chemistry
Hart, H., Department of Chemistry, Michigan State University, East Lansing, MI 48824, United States
Dunkelblum, E., Department of Chemistry, Michigan State University, East Lansing, MI 48824, United States
Irradiation of the three isomeric benzocycloheptadienones 10, 14, and 15 produces in each case a trans intermediate which can be trapped by furan. In the absence of a trapping agent, cyclobutane dimers are formed whose stereochemistry, established mainly by X-ray diffraction on crystals, differs for each of the three substrates (10 → 12; 14 → 18, 19; 15 → 22, 23, 24, 25). The formation of head-to-tail dimers 23 and 25 is novel and argues against a diradical mechanism. Dimer stereochemistry corresponds to a π;2 s + π2 a ground state cycloaddition between two trans species for 10, a trans + cis species for 14, and both types for 15. A rationale in terms of the most strained trans intermediate being the least selective for its reaction partner is proposed to explain the results. © 1979 American Chemical Society.
פותח על ידי קלירמאש פתרונות בע"מ -
הספר "אוצר וולקני"
אודות
תנאי שימוש
Stereochemistry of the cyclobutane dimers of trans-cycloheptenones
44
Hart, H., Department of Chemistry, Michigan State University, East Lansing, MI 48824, United States
Dunkelblum, E., Department of Chemistry, Michigan State University, East Lansing, MI 48824, United States
Stereochemistry of the cyclobutane dimers of trans-cycloheptenones
Irradiation of the three isomeric benzocycloheptadienones 10, 14, and 15 produces in each case a trans intermediate which can be trapped by furan. In the absence of a trapping agent, cyclobutane dimers are formed whose stereochemistry, established mainly by X-ray diffraction on crystals, differs for each of the three substrates (10 → 12; 14 → 18, 19; 15 → 22, 23, 24, 25). The formation of head-to-tail dimers 23 and 25 is novel and argues against a diradical mechanism. Dimer stereochemistry corresponds to a π;2 s + π2 a ground state cycloaddition between two trans species for 10, a trans + cis species for 14, and both types for 15. A rationale in terms of the most strained trans intermediate being the least selective for its reaction partner is proposed to explain the results. © 1979 American Chemical Society.
Scientific Publication
You may also be interested in