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Thermolysis of Imidates: A New Method for the Generation of Carbonyl Ylides
Author(s) -
Nikolaev Vsevolod V.,
Linden Anthony,
Heimgartner Heinz
Publication year - 2007
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.200790239
Subject(s) - chemistry , ylide , isomerization , benzaldehyde , malonate , thermal decomposition , stereoselectivity , medicinal chemistry , molecule , double bond , decomposition , photochemistry , stereochemistry , organic chemistry , catalysis
Thermolysis of dimethyl 2‐[(3‐oxo‐3 H ‐isoindol‐1‐yl)oxy]malonate ( 8 ) promotes a [1,4]‐H shift in the imidic NCOCH fragment of the starting molecule, which leads to a reactive carbonyl ylide. This carbonyl ylide can be trapped by the CN bond of imidates and imines, as well as the CO bond of benzaldehyde. The corresponding cycloadducts 11, 14 , and 16 are formed regioselectively in good yields (60–95%) and with high stereoselectivity. In the case of 11 , the minor cycloadduct in solution undergoes an isomerization to give the more stable stereoisomer. The structures of two cycloadducts, i.e. , 11a and 14a , have been established by X‐ray crystallography.