Tabrez Khan

Total Synthesis and Structural Revision of Antibiotic CJ-16,264†

The total synthesis and structural revision of antibiotic CJ-16,264 is described. Starting with citronellal, the quest for the target molecule featured a novel bis-transannular Diels-Alder reaction that casted stereoselectively the decalin system and included the synthesis of six isomers before demystification of its true structure.

(1′S,6′S,8′S,9′R)-9′-Bromo-12′-oxa­spiro­[1,3-dioxolane-2,4′-tricyclo­[6.3.1.01,6]dodeca­ne]

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[benzo[7]annulene-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.