Herein, we describe the total synthesis of ervaoffine J & K from a central intermediate. Ervaoffine J was synthesized in eight steps in 14 % yield. Our strategy features an aerobic Winterfeldt oxidation to introduce the 4-quinolone moiety. Ervaoffine K was produced in ten steps and 10 % yield. The synthesis leveraged (bromodifluoromethyl)-trimethylsilane to induce a regioselective von Braun-type C-N bond fragmentation. This C-N bond cleavage unveiled the tetrasubstituted all-syn cyclohexane core of ervaoffine K and enabled the completion of its synthesis.
We describe the gram-scale total synthesis of (±)-ibogamine in nine steps and 24% overall yield. The approach features a Mitsunobu fragment coupling and macrocyclic Friedel-Crafts alkylation to establish the nitrogen-containing core of ibogamine. A regio- and diastereoselective hydroboration allows for simultaneous formation of the tetrahydroazepine and isoquinuclidine ring systems via sulfonamide deprotection and concomitant intramolecular cyclization.
Molecular Structure , Alkylation , Cyclization
