208. Aminierende reduktive Kupplung aromatischer Aldehyde mit niedervalenten Titan-Reagenzien zu 1,2-Diarylethylendiaminen

Article abstract of DOI:10.1002/hlca.19870700826

In a novel McMurry-type one-pot reaction, aromatic aldehydes and secondary amines are coupled to give the N,N,N',N'-tetralkyl-1,2-diarylethylendiamines 1-22 (Table 3).To this end, a lithium dialkylamide is added to an aromatic aldehyde to give the adduct B which is then treated with 1 equiv. of TiCl4 to yield a coloured suspension of a reagent synthetically equivalent to a iminium salt (C/D in Scheme 4).After treatment with a low-valent Ti reagent which is prepared by reduction of TiCl4 with either K or, preferably, Mg, the coupling products are isolated in 23 to 81 percent yield as a 1:1 mixture of the diastereoisomers (meso- and rac-form).These are separated either by chromatography or by crystallization and characterized.