Hydroaminoalkylation of Allylsilanes and a One-Pot Procedure for the Synthesis of 1,5-Benzoazasilepines.

Allylsilanes undergo highly regioselective intermolecular alkene hydroaminoalkylation with secondary amines in the presence of a titanium mono(formamidinate) catalyst. Corresponding reactions of a suitable allyl(2-bromophenyl)silane which exclusively deliver the branched hydroaminoalkylation products combined with a subsequent Buchwald-Hartwig amination result in the development of an elegant one-pot procedure for the synthesis of literature-unknown silicon analogues of 1,5-benzodiazepines, the so-called 1,5-benzoazasilepines.

One-Pot Procedure for the Synthesis of 1,5-Benzodiazepines from N-Allyl-2-bromoanilines.

A new one-pot procedure that includes an initial titanium-catalyzed intermolecular hydroaminoalkylation of N-allyl-2-bromoanilines with N-methylanilines and a subsequent intramolecular Buchwald-Hartwig amination directly gives access to pharmacologically relevant 1,5-benzodiazepines. The process takes advantage of the excellent regioselectivity of the initial hydroaminoalkylation performed in the presence of a titanium mono(formamidinate) catalyst and the fact that the exclusively formed branched hydroaminoalkylation products can only undergo palladium-catalyzed cyclization to 1,5-benzodiazepines.