[2+2]-Photocycloaddition von Cyclohexen an 2-Acetyl-5,5-dimethyl-1,3-cyclohexandion und 3-Acetyl-1,5,5-trimethyl-2,4-pyrrolidindion
作者:Hans-Georg Henning、Giedrius Mazunaitis
DOI:10.1007/bf01045301
日期:——
Irradiation of solution of excess cyclohexene and 2-acetyl-5,5-dimethyl-1,3-cyclohexanedione (1), and 3-acetyl-1,5,5-trimethyl-2,4-pyrrolidinedione (4) results mainly in the formation of 1,5-diones 2 and 5. These originate from intermediate cycloadducts of cyclohexene and the exo-enols of the cyclic 1,3-diketones. The yields decrease with increasing polarity of the solvent. In solution 2 and 5 are in equilibrium with the cyclic hemiacetales 3 and 6.