Method for preparing boric acid ester by catalyzing hydroboration reaction of imine and borane with disilazane rare earth complex

The invention relates to a method for preparing a boric acid ester by catalyzing hydroboration reaction of an imine and a borane with a disilazane rare earth complex. The method comprises the following steps: under the protection of nitrogen, uniformly mixing the imine, the disilazane rare earth complex and the borane in sequence, and reacting to obtain an amino borane. According to the invention,the synthesis reaction of the imine and pinacol borane is catalyzed with the disilazane rare earth complex for the first time, and the novel high efficiency catalyst used for catalyzing hydroborationreaction is invented. The synthesis method of the disilazane rare earth complex is simple, not only the application of the disilazane rare earth complex is expanded, but also the synthesis reaction method of the imine and pinacol borane is enriched. The dosage of the catalyst is only 2% of the molar weight of the imine; the reaction speed is high, the yield can reach 80% or above after reaction is conducted for 3 hours, c