A facile one-pot synthesis of protoberberines from readily accessible 1,2,3,4-tetrahydroisoquinoline-1-carbonitriles and 1,2-bis(bromomethyl)arenes is described. The reaction cascade comprises four consecutive transformations, all of which can be effected under a single set of conditions. Ten protoberberines, including the alkaloids pseudopalmatine and pseudoepiberberine, were prepared in yields up to 86% according to this strategy. No chromatographic purification of the products is required, and the route is devoid of any protecting group manipulations.

A One-Pot Cascade to Protoberberine Alkaloids via Stevens Rearrangement of Nitrile-Stabilized Ammonium Ylides. -This method gives access to quaternary protoberberines including naturally occurring pseudopalmatine (IIIf) and pseudoepiberberine (IIIg). -(LAHM, G.; DEICHMANN, J.-G.; RAUEN, A. L.; OPATZ*, T.; J. Org. Chem. 80 (2015) 3, 2010-2016, http://dx.doi.org/10.1021/jo502842s ; Inst. Org. Chem., Johannes-Gutenberg-Univ., D-55128 Mainz, Germany; Eng.) -M. Tismer 26-209