Metal-Free One-Pot Annulative Coupling of 2-Hydroxybenzaldehydes with β-Ketothioamides: Access to Diverse 2-Arylimino-2 H -Chromenes.
Pragya PaliDhananjay YadavSubash Chandra SahooMaya Shankar SinghPublished in: The Journal of organic chemistry (2022)
A concise and practical one-pot sustainable approach for expedient synthesis of 2-arylimino-2 H -chromenes by two-component cascade [4 + 2] annulative coupling of easily available 2-hydroxybenzaldehydes with β-ketothioamides has been developed in good yields for the first time. Remarkably, metal- and additive-free conditions, use of simple K 2 CO 3 as a mild base, open atmosphere, exclusive regioselectivity, step/atom economy, nonhazardous reagents, and easy purification are added characteristics to the strategy. This annulative protocol will not only provide an efficient method to access diverse chromene scaffolds, but also enrich the research domain of β-ketothioamides.