Chemodivergent synthesis of functionalized methanodibenzo[b,f][1,5]diazocin-13-ylmethanones and tetrahydroquinolines via solvent-dependent AB2 and A2B2 multicomponent annulation reactions

A solvent-dependent chemodivergent approach was established for the synthesis of 6,12-methanodibenzo[b,f][1,5]diazocin-13-ylmethanones and 2,3,4-trisubstituted 1,2,3,4-tetrahydroquinolines involving two distinct multicomponent processes under basic conditions. The AB2 three-component and A2B2 four-component reactions between 2-aminoarylaldehydes and aryl methyl ketones under basic conditions afforded 6,12-methanodibenzo[b,f][1,5]diazocin-13-ylmethanones (up to 95% yield) and trisubstituted tetrahydroquinolines (up to 84% yield), respectively, based on the nature of the solvent employed. The skeletal diversity and complexity were attained in these high atom- and step-economical processes by creating four new bonds in a single synthetic operation from readily available simple starting materials.