One-Pot Organocatalytic Enantioselective Domino Double-Michael Reaction and Pictet-Spengler–Lactamization Reaction. A Facile Entry to the “Inside Yohimbane” System with Five Contiguous Stereogenic Centers

An expedited method was developed for the enantioselective synthesis of dodecahydrobenz[<i>a</i>]indolo[3,2-<i>h</i>]quinolizine containing five contiguous stereogenic centers with high enantioselectivities (>99% ee). The methodology comprises a domino organocatalytic double Michael reaction and Pictet-Spengler–lactamization reaction. The structures and absolute configurations of the appropriate products were confirmed by X-ray analysis