Gold-catalyzed formal [4π + 2π]-cycloadditions of propiolate derivatives with unactivated nitriles?

Chemical Science Pub Date: 2015-07-20 DOI: 10.1039/C5SC01950H

Abstract

Gold-catalyzed hetero-[4π + 2π]-cycloadditions of tert-butyl propiolates with unactivated nitriles are described; the resulting 6H-1,3-oxazin-6-ones are not easily accessible via conventional methods. This new finding enables a one-pot gold-catalyzed synthesis of highly substituted pyridines through sequential gold-catalyzed reactions of tert-butyl propiolates with nitriles, and then with electron-deficient alkynes in the same solvent. The utility of these [4 + 2]-cycloadditions is further expanded with various aldehydes, ketones and 2-phenyloxetane, yielding satisfactory yields of cycloadducts.

Graphical abstract: Gold-catalyzed formal [4π + 2π]-cycloadditions of propiolate derivatives with unactivated nitriles
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