CARBENE - 23. PHOSPHENE: - UND -CYCLOADDITION VON (DIPHENYLMETHYLEN) PHENYLPHOSPHAN-OXID MIT α,β-UNGESAETTIGTEN KETONEN

Article abstract of DOI:10.1016/S0040-4020(01)97682-3

The photolysis of 1 produces the carbene 2, which is transformed into the short lived phosphene 4 by phenyl migration.With the α,β-unsaturated ketones 6a-d in a <2+2> cycloaddition 4 yields 1,2λ⁵-oxaphosphetanes 7a-d.The heterocycles partially undergo a photofragmentation, which produces the olefines 9a-d and the heterocumulene 8.If 4 is a generated form 1 under thermal conditions in the presence of 6a-c, formation of four membered rings and fragmentation is observed too; in addition 4 undergoes a <4+2>-cycloaddition with the hetero-1,3-dienes 6a-c leading to 15a-c.This behaviour corresponds to that of the carbonylanalogue diphenylketene with 6a (formation of CO2 and 9a via the β-lactone 16 such as of 17)