Diarylborinic acid derivatives as a catalytic iminium ion generator in the mannich-type reaction using secondary amines, aldehydes, and ketene silyl acetals
In a series of papers, [7] we have developed aminoborane derivative 1 as a new boron-based iminium ion generator for Mannich-type reaction, [8] reductive amination, [9] and Ugi-type reactions (Figure 1). [10] [11] The iminium ion generator allows the reactions to be carried out under nonacidic reaction conditions, opening up the new possibilities for the synthesis of amine derivatives. However, the requirement of stoichiometric amounts of the commercially unavailable ...
