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Photochemical Synthesis of Cyclic 2‐(2,2‐Dimethylpropylidene)‐1,3‐dicarbonyl Compounds
Author(s) -
Hobel Klaus,
Margaretha Paul
Publication year - 1989
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19890720513
Subject(s) - chemistry , photodissociation , pyran , tricyclic , ring (chemistry) , cleavage (geology) , alkyl , medicinal chemistry , stereochemistry , photochemistry , organic chemistry , geotechnical engineering , fracture (geology) , engineering
Photolysis (λ = 254 nm) of 4‐( t ‐Bu)‐substituted [ b ]‐fused bi‐ and tricyclic pyrandiones 5 affords title compounds 4 in good yields as well as small amounts of spiroalkanediones 8 . The alkyl‐substitution pattern at C(4) of the pyran ring in 5 determines the relative amount of α vs. β‐cleavage products obtained from the primarily formed acyl‐vinyloxy biradical.