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

Chiral spirocyclic phosphine-nitrogen-phosphine tridentate ligand SpiroPNP wherein, having the structure of general formula I or its optical isomer or a racemate thereof, or a catalytically acceptable salt thereof,

• Wherein, R1 is selected from C1-C10 hydrocarbyl, phenyl, substituted phenyl, 1-naphthyl, 2-naphthyl, heteroaryl or benzyl, and the substituent on the phenyl group is C1-C10 hydrocarbyl, alkoxy, the number of substituents is 1 to 5, and the heteroaryl is furyl, thienyl or pyridyl;
• R2, R3, R4, R5 are independently selected from H, C1˜C10 alkyl, phenyl, substituted phenyl, 1-naphthyl, 2-naphthyl, heteroaryl or benzyl, and the substituent on said substituted phenyl is C1-C10 hydrocarbyl or alkoxy, with a substituent amount of 1-5, and said heteroaryl is furyl, thienyl or pyridyl, or C1-C10 alkoxy, or R2˜R3, R4˜R5 are incorporated into C3˜C7 aliphatic ring or aromatic ring, R2, R3, R4, R5 can be the same or different,
• R6 and R7 are independently selected from H, C1˜C10 alkyl, C1˜C10alkoxy, C1˜C10 aliphatic amido group, and n=0˜3, or when n≥2, two adjacent R6 groups or two adjacent R7 groups can be incorporated into C3-C7 aliphatic ring or aromatic ring, and R6, R7 can be the same or different,
• R8, R9 an H, C1-C10 alkyl, C3-C10 alkoxy, phenyl, substituted phenyl, 1-naphthyl, 2-naphthyl, heteroaryl or benzyl, and the substituent on said substituted phenyl is C1-C10 alkyl or alkoxy with a substituent amount of 1-5, and said heteroaryl is furyl, thienyl or pyridyl, and adjacent R8 and R9 groups can be incorporated into rings through the C2-C4 carbon chain and carbon chains containing nitrogen atom, oxygen atom or sulfur atom, and through aromatic rings, or heteroaromatic rings, and R8, R9 can be the same or different.