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Ammoniumyl Salt‐Induced Diels‐Alder Reaction of Ketenes—Control of [2 + 2] vs. [4 + 2] Selectivity
Author(s) -
Schmittel Michael,
von Seggern Heinke
Publication year - 1991
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199109991
Subject(s) - cycloaddition , salt (chemistry) , selectivity , chemistry , medicinal chemistry , diels–alder reaction , catalysis , organic chemistry
The [2 + 4] cycloaddition products 4 are formed from 1 and 2 when the ammoniumyl salt 3 is added as initiator. The reaction is complete in only a few minutes at 0°C. In the absence of 3 , compounds 1 and 2 only react at 80°C over two days, leading to [2 + 2] cycloadducts. An acid‐catalyzed side reaction also produces cycloheptadienone. R = p ‐tolyl, p ‐anisyl.