Controlled crisscross annulation

A controlled crisscross annulation strategy has been used to construct the eight-membered ring compound (457) has been prepared in five steps. The key reaction was conducted under electrolytic reduction conditions to afford the benzazocine derivative (458), which was transformed to (459) in 20 steps. Oxidation of the alcohol and further treatment with /-butyldimethylsilyltriflate gave the tricyclic compound (460) (Scheme 32) <88JOC5355>. 

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