Plant coumarins: XV. Oreoselone in the synthesis of 3-[(Z)-alkenyl]- and 3-(1H-1,2,3-triazol-4-yl)psoralens

Sonogashira reaction of 2-isopropyl-3-(trifluoromethanesulfonyloxy)psoralen with terminal arylacetylenes gave 2-isopropyl-3-(arylethynyl)psoralens which were converted into the corresponding Z -alkenes by reduction with hydrogen in the presence of Lindlar catalyst or by thermal decomposition of preliminarily prepared Ti(II)–alkyne complexes. The reaction of 2-isopropyl-3-(trifluoromethanesulfonyloxy)psoralen with trimethylsilylacetylene afforded 2-isopropyl-3-[(trimethylsilyl)ethynyl]psoralen which reacted with 4-(ω-azidoalkyl) phenols in the presence of copper(I) bromide and triethylamine to produce 3-{1-[ω-(4-hydroxyaryl)-alkyl]-1 H -1,2,3-triazol-4-yl}-2-isopropylpsoralens.