Tris(2,6-diphenylbenzyl)amine (TDA) and tris(2,6-diphenylbenzyl)phosphine (TDP) with unique bowl-shaped structures: synthetic application of functionalized TDA to chemoselective silylation of benzylic alcohols

A new strategy for obtaining the formal steric hindrance of tertiary amines by remote steric factors is described by designing the bowl-shaped, structurally unique tris(2,6-diphenylbenzyl)amine (TDA). In addition to its structural uniqueness, TDA possesses the rich electronic atmosphere derived from three 2,6-diphenylbenzyl moieties, thereby allowing the chemoselective silylation of benzylic alcohols preferentially over other alcohols based on the effective aromatic π,π interaction. This approach of preparing TDA is also applicable to the new synthesis of tris(2,6-diphenylbenzyl)phosphine (TDP).