Direct aldol and tandem Mannich reactions in room temperature ammonia solutions

An economical, simple, and efficient direct aldol reaction via the double activation of both aldehydes and ketones by ammonia has been developed. An unprecedented tandem Mannich reaction was observed when hydroxybenzaldehydes, pyrrole-2-carboxyaldehyde, and indole-3-carboxyaldehyde were employed to afford 2,2-dimethyl-6-aryl-4-pyrilidinones in moderate to good yields.