Domino Aldol-SAr-Dehydration Sequence for [3+3] Annulations to Prepare Quinolin-2(1)-ones and 1,8-Naphthyridin-2(1)-ones.

A domino aldol-SAr-dehydration [3+3] annulation strategy has been utilized to fuse six-membered cyclic amides onto aromatic substrates. 2-Arylacetamides have been reacted with 2-fluorobenzaldehyde derivatives activated toward SAr reaction by an electron-withdrawing substituent (NO, CN, CF, COMe) at C5 to prepare 3,6-disubstituted quinolin-2(1)-ones. Additionally, 3-substituted 1,8-naphthyridin-2(1)-ones have been similarly derived from 2-fluoronicotinaldehyde. Fifteen examples are reported, and two possible mechanistic scenarios are presented and discussed.