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Photochemistry of ethyl 2,3‐dihydro‐2,2‐dimethyl‐3‐oxo‐1 H ‐pyrrole‐1‐carboxylate
Author(s) -
Patjens Jan,
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.19890720818
Subject(s) - chemistry , cycloaddition , furan , thiophene , pyrrole , heteroatom , yield (engineering) , medicinal chemistry , halogenation , photochemistry , carboxylate , dimethyl fumarate , enone , ene reaction , organic chemistry , catalysis , ring (chemistry) , psychology , materials science , psychiatry , multiple sclerosis , metallurgy
The title compound 7 is obtained by reductive dehalogenation from 4‐bromo‐2,3‐dihydro‐2,2. ‐dimethyl‐3‐oxo‐1 H ‐pyrrole‐1‐carboxylate ( 8 ) in 90% yield, Aza‐enone 7 undergoes [2 + 2] cycloaddition from the triplet state with both electron‐rich and electron‐deficient alkenes. The behaviour of 7 in light‐induced reactions is compared to those of 2,2‐dimethyl‐3(2 H )‐furanone ( 1a ) and of the corresponding thiophenone 1b . In the photodimerization and the cycloaddition to either 2,3‐dimethylbut‐2‐ene or to dimethyl maleate of these ketonic five‐membered heterocycles with one heteroatom, the overall efficiency increases in going from the furan 1a to the thiophene 1b and to the pyrrole 7 .