N (α)-(2-Oxo-2H-1-benzopyran-4-yl) Weinreb-α-aminoamides were prepared from 4- chlorocoumarin and α-aminoacid derivatives. Their reaction with organometallic compounds (RLi or RMgBr) and subsequent cyclization of ketones thus obtained, give [1] benzopyrano [4, 3-b] pyrrol-4 (1H)-ones. Starting from proline derivatives, simultaneously with the pyranone-pyrrole fusion, we establish an interesting procedure for the formation of ...