Thermolysis of Imidates: A New Method for the Generation of Carbonyl Ylides |
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Authors: | Vsevolod V. Nikolaev Anthony Linden Heinz Heimgartner |
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Affiliation: | 1. Organisch‐Chemisches Institut der Universit?t Zürich, Winterthurerstrasse 190, CH‐8057 Zürich, (phone: +41?44?635?4282;2. fax: +41?44?635 6812);3. Saint‐Petersburg State University, University prosp. 26, Saint‐Petersburg, 198504, Russia |
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Abstract: | Thermolysis of dimethyl 2‐[(3‐oxo‐3H‐isoindol‐1‐yl)oxy]malonate ( 8 ) promotes a [1,4]‐H shift in the imidic ? N?C? O? CH? fragment of the starting molecule, which leads to a reactive carbonyl ylide. This carbonyl ylide can be trapped by the C?N bond of imidates and imines, as well as the C?O 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. |
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Keywords: | Carbonyl ylides Imidates Cycloadditions Thermolysis Ylides 1,3‐Oxazolidines X‐Ray crystallography |
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