Date Published: August 01, 2012
Publisher: International Union of Crystallography
Author(s): Goverdhan Mehta, Tabrez Babu Khan.
In an endeavor directed towards the construction of the oxabicyclic[3.2.1]octane segment present in the bioactive natural products of cortistatins and icetexanes genre, the title compound, C13H19BrO3, was synthesized from (4aR,9aS)-1,3,4,4a,5,6,9,9a-octahydrospiro[benzoannulene-2,2′-[1,3]dioxolane]-4a-ol via a transannular bromo-etherification protocol. The six-membered ring adopts a twist-boat conformation, while the fused cycloheptane ring adopts a chair conformation. The crystal packing is effected through two distinct intermolecular C—H⋯O hydrogen-bond patterns and molecules are arranged to define an interesting motif along the b axis.
For the isolation and biological activity of cortistatins, see: Aoki et al. (2006 ▶, 2007 ▶); Watanabe et al. (2007 ▶); Zhao (2010 ▶) and for icetexanes, see: Esquivel et al. (1995 ▶); Uchiyama et al. (2005 ▶). For synthetic approaches towards the construction of the oxabicyclic core of cortistatins, see: Zhao (2010 ▶); Hardin Narayan et al. (2010 ▶) and references cited therein. For their use in the treatment of blindness, see: Czako et al. (2009 ▶). For the construction of relevant 6/7 fused-ring systems involving ring-closing metathesis, see: Mehta & Likhite (2008 ▶, 2009 ▶). For an example of the exploitation of transannular bromoetherification towards natural products synthesis, see: Mehta & Sen (2010 ▶); Mehta & Yaragorla (2011 ▶).