Investigations into the construction of the penta­substituted ring C of Neosurugatoxin – a crystallographic study

Jones, AM, Storey, JMD and Harrison, WTA (2016) Investigations into the construction of the penta­substituted ring C of Neosurugatoxin – a crystallographic study. Acta Crystallographica Section E: Structure Reports Online, 72 (1). pp. 44-48. ISSN 2056-9890

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Abstract

The crystal structures of three cyclo­penta­[c]furans with various substituents at the 4-, 5- and 6-positions of the ring system are reported, namely, (±)-(3aR,4S,5S,6aS)-4-methyl-5-phenyl­hexa­hydro-1H-cyclo­penta­[c]furan-4,5-diol, C14H18O3, (I), (±)-(3aR,4S,5S,6aS)-4-benz­yloxy-4-methyl-5-phenyl­hexa­hydro-1H-cyclo­penta­[c]furan-5-ol, C21H24O3, (II), and (±)-(1aR,1bS,4aR,5S,5aR)-5-benz­yloxy-5-methyl-5a-phenyl­hexa­hydro-2H-oxireno[2',3':3,4]cyclopenta­[1,2-c]furan, C21H22O3, (III). The dominant inter­action in (I) and (II) is an O-H...O hydrogen bond across the bicyclic 5,5-ring system between the non-functionalized hy­droxy group and the tetra­hydro­furan O atom, which appears to influence the envelope conformations of the fused five-membered rings, whereas in (III), the rings have different conformations. A weak intra­molecular C-H...O inter­action appears to influence the degree of tilt of the phenyl ring attached to the 5-position and is different in (I) compared to (II) and (III).