Intramolecular Sakurai Allylation of Geminal Bis(silyl) Enamide with Indolenine. A Diastereoselective Cyclization To Form Functionalized Hexahydropyrido[3,4‑b]Indole

A fluoride-promoted intramolecular Sakurai allylation of geminal bis­(silyl) enamide with indolenine has been developed. The reaction facilitates an efficient cyclization to give hexahydro­pyrido­[3,4-b]­indoles in good yields with high diastereoselectivity. The resulted cis, trans-stereochemistry further enables the ring-closing metathesis (RCM) reaction of two alkene moieties, giving a tetracyclic N-hetereocycle widely found as the core structure in akuammiline alkaloids.