The oligoselective syntheses of polyacene derivatives

Abstract

The syntheses of the undecacene derivatives rel-(1R,4S,6R,6aR,8S, 10S,11aR,12R,14S,17R,19S,19aS,21R,23R,24aS,25S)-1,4: 6,25:8,23:10,21:12,19:14,17-hexaepoxy-1,4,6,6a.7,8,10,11,11a,12,14, 17,19,19a,20,21,23,24,24a,25-eicosahydroundecacene (6) and rel-(1R,4S,6S,6aS,8R,10R,11aS,12S,14S,17R,19R,19aR,21S,23S,24aR,25R)- 1,4:6,25:8,23:10,21:12,19:14,17-hexaepoxy-1,4,6,6a,7,8,10,11,11a, 12,14,17,19,19a,20,21,23,24,24a,25-eicosahydroundecacene (7) are reported. The initial stages of a reaction sequence in which thermally-promoted and high pressure-promoted cycloadditions between the anti-bisdienophile 1a and the bisdiene 4 are used alternately to obtain the polyacene derivatives rel-(1R,4S,5aS,6S,8S,8aS,10S,13R,14aR,15R,17R,17aR)-1,4:6,17:8,15: 10,13-tetraepoxy-1,4,5,5a,6,8,8a,9,10,13,14,14a,15,17,17a,18- hexadecahydro-2,3,10,11-tetramethylideneheptacene (8) and rel-(1R,4S,6S,6aS,8S,9aR,10R,12R,12aR,14S,15aS,16S,18S,21R,23R,23aR, 25R,26aS,27S,29S,29aS,31R,32aR,33R)-1,4:6,33:8,31:10,29:12,27:14,25: 16,23:18,21-octaepoxy-1,4,6,6a,7,8,9,9a,10,12,12a,13,14,15,15a,16, 18,21,23,23a,24,25,26,26a,27,29,29a,30,31,32,32a,33- dotriacontahydropentadecacene (9) with complete oligoselectivity and treble diastereoselectivity in each step are described.