Synthesis and properties of methano-bridged tetradehydro-[20]-, -[24]-, -[26]-, -[28]-, -[30]- and -[32]-annulenediones

Abstract

The title annulenediones 4-9 have been synthesized by first an aldol condensation of cyclohepta-1,3,5-triene-l,6-dicarbaidehyde 10 or its vinylogous dialdehydes 11-14 with acetone to afford the dimethyl diketones 16-20 and then by a second aldol condensation of 1,6-diacetyIcyclohepta-1,3,5-triene 15 or the dimethyl diketones 16-20 with (Z)-3-methylpent-2-en-4-ynal 21, followed 98

Nanochannel Array within a Multilayered Network of a Planarized Dehydro[24]annulene

“…The average deviation from the mean plane defined by the 24 carbons on the macrocycle perimeter is only 0.034(1) Å, with the maximum deviation being 0.068(1) Å. This near-perfect planarity is unusual considering that no annulation , or intra-annular bridging constraints are present in the molecule . In addition, tetraol 1c forms a network of hydrogen bonds in the crystal: a square motif of O···H contacts leads to a corrugated sheet built from the planar macrocycles (Figure g).…”