配座制御を設計基盤とした新規不斉配位子の開発と応用

抄録

We developed novel chiral ligands based on concept of conformation control.
At first, we developed an N-heterocyclic carbene ligand 1. The substituent R on the N atom in the carbene ligand 1 may be conformationally flexible, but if the complexation of 1 and metal is reflected by the asymmetric center in 1, a more stable complex 2a, in which orientation of the substituent R on the N atom is fixed, is expected to be selectively formed (figure 1).
Next, we developed a hemilabile P-P=O ligand 3 with both soft and hard coordinated center within one molecule. Figure 2 shows the possible design of 3 such that the soft Ar₂P group coordinates with a soft metal and the hard Ar₂P=O group coordinates with a hard metal. These two coordinations allow a fixed conformation of the complex between the hemilabile ligand 3 and metals (soft and hard), leading to the creation of a favorable asymmetric environment.

fig.1