Preparation method for and application of chiral spirocyclic phosphine-nitrogen-phosphine tridentate ligand and iridium catalyst thereof

A chiral spirocyclic phosphine-nitrogen-phosphine tridentate ligand SpiroPNP comprising a compound having a structure of general formula I, its optical isomer, a racemate thereof, or a salt thereof as shown below:

• wherein R1 is selected from the group consisting of C1-C10 hydrocarbyl, phenyl, substituted phenyl, 1-naphthyl, 2-naphthyl, heteroaryl and benzyl, and the substituent on the phenyl group is C1-C10 hydrocarbyl, alkoxy, the number of substituents of the phenyl group is 1 to 5, and the heteroaryl is selected from the group consisting of furyl, thienyl and pyridyl;
• R2, R3, R4 and R5 are independently selected from the group consisting of H, C1-C10 alkyl, phenyl, substituted phenyl, 1-naphthyl, 2-naphthyl, heteroaryl and benzyl, and the substituent on the phenyl group is C1-C10 hydrocarbyl or alkoxy, the number of substituents on the phenyl group of R2, R3, R4, R5 are 1 to 5, and the heteroaryl is selected independently from the group consisting of furyl, thienyl and pyridyl, and the R2 and R3, R4 and R5 are optionally formed into C3-C7 aliphatic ring or heteroaromatic ring,
• R6 and R7 are independently selected from the group consisting of H, C1-C10 alkyl, C1-C10 alkoxy and C1-C10 aliphatic amido group, and n=0˜3, or when n≥2, two adjacent R6 groups or two adjacent R7 groups can be formed into C3-C7 aliphatic ring or heteroaromatic ring,
• R8, R9 are selected from the group consisting of H, C1-C10 alkyl, C1-C10 alkoxy, phenyl, substituted phenyl, 1-naphthyl, 2-naphthyl, heteroaryl benzyl, C2-C4 carbon chain and carbon chains containing nitrogen atom, oxygen atom or sulfur atom, and the substituent on the phenyl group is C1-C10 alkyl or alkoxy, the number of a substituents of the phenyl group of R8, R9 are 1 to 5, and said heteroaryl is selected independently from the group consisting of furyl, thienyl and pyridyl, and adjacent R8 and R9 groups can be formed into rings and R8, R9 can be the same or different.