Base-Mediated Generation of Ketenimines from Ynamides: [3+2] Annulation with Azaallyl Anions.

19 October 2020, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Under basic conditions and heat, ynamides can serve as precursor to ketenimines, whose synthetic potential is often hampered by their difficulty of acces. Herein, we report that they can undergo a [3+2] cycloaddition with 2-azaallyl anions, obtained from benzylimines under the same reaction conditions. This reaction between two highly reactive intermediates, both generated in situ from bench stable starting materials, gives access to various nitrogen-rich heterocycles. The reaction usually proceeds with excellent diastereoselectivity, in favor of the cis adduct. Deuteration experiments and DFT calculation helped rationalize the regio and stereo-selectivity of the process as well as the formation of side-products.

Keywords

Ynamides
azallyl anion
cycloaddition
3+2

Supplementary materials

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SupportingInfo3+2
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Gaussian output3+2
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cmpd 7ac todeposit
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cmpd 6ag deposit
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Spectres3+2
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