Oxidative Copper(I)-Mediated Cycloamination. Preparation and Reactions of Heteroaromatic Benzylic Zinc Compounds. Novel Preparation of Tertiary Benzylic and Phenethylic Amines

1. It was demonstrated that the two-fold deprotonation of
benzofuran-3-yl- and benzothiophen-3-ylanilines using nBuLi,
followed by transmetalation using CuCl·2LiCl afforded cyclic
amidocuprates which were readily oxidized using
2,3,5,6-tetrachlorobenzo-p-quinone (“chloranil”) to furnish new
tetracyclic benzofuro- and benzothieno[2,3-b]indoles. 2. A method
was developed, starting from heteroaryl organometallics, for the
synthesis of non-conjugated heteroaromatic benzylic zinc compounds
which could be reacted with a wide range of electrophiles. 3. The
preparation of mixed aminals from Mannich’s cation and a range of
metal amides was performed and their subsequent ionization to
(methylene)iminium ions using trifluoroacetic anhydride was
achieved. Trapping of these iminium ions with a range of
organometallic substrates in a one-pot fashion led to the efficient
formation of sterically hindered tertiary benzylic and phenethylic
amines.