Org Lett 2019 01 8;21(2):519-523. Epub 2019 Jan 8.
Institut für Organische Chemie , Universität Leipzig , Johannisallee 29 , 04103 Leipzig , Germany.
We describe herein an organocatalytic, diastereo- and enantioselective [6 + 2]-cycloaddition toward the synthesis of densely substituted 2,3-dihydro-1 H-pyrrolizines bearing three contiguous stereogenic centers which are obtained with good yields, as single diastereomers, and with excellent enantioselectivity. A crucial feature of this one-step process leading to a prominent structural motif in many biologically active natural products is a BINOL-derived phosphoric acid catalyzed reaction of 1 H-pyrrole-2-yl carbinols with 2-vinylindoles via the corresponding hydrogen-bonded chiral 2-methide-2 H-pyrroles. Read More