Stereospecific Insertion of Cyclic Amidines into Aryl-Substituted Cyclopropanones: Access to Complex Spirocyclic
Richard Herzog1, Ishika Agrawal1, Heinrich F von Köller2
1Institute of Organic Chemistry, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg im Breisgau, Germany.
Abstract:
A facile, catalyst-free protocol to access structurally complex spirocyclic aminals from cyclopropanone surrogates and amidines is reported. The two-component reaction is described as a stereospecific insertion of the amidine C═N bond into the C1-C2 bond of the cyclopropanone via the addition of N to the carbonyl group, followed by ring enlargement. The products display similarities to numerous biologically active oligocyclic systems. Further structural diversification is demonstrated, and a proposed mechanism based on experimental and computational evidence is provided.
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