TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The method comprises (i) dissolving isobutylboronic acid and (1S, 2S, 3R, 5S)-(+)-2,3-pinanediol in a molar ratio of 1:1-3 in a reaction solvent, and reacting by stirring at room temperature to obtain protected isobutylboronic acid pinanediol ester i.e. (1S,2S,6R,8S)-4-isobutyl-2,9,9-trimethyl-3,5-dioxa-4-bora-tricyclo(6.1.1.0(2,6))decane (I), where the reaction solvent is cyclohexane, dimethyl ether, diethyl ether, isopropyl ether or other hydrocarbyl ether solvent, (ii) adding (I), lithium diisopropylamide (LDA) and anhydrous zinc chloride in a molar ratio of 1:1-2:1-4 into an organic solvent and carrying out rearrangement reaction to obtain (1S,2S,6R,8S)-4-((S)-1-chloro-3-methyl-butyl)-2,9,9-trimethyl-3,5-dioxa-4-bora-tricyclo(6.1.1.0(2,6))decane (II), (iii) taking (II) and lithium hexamethyldisilazane (LiHMDS in 1N tetrahydrofuran solution) or sodium hexamethyldisilazane (NaHMDS in 1N tetrahydrofuran solution) in a molar ratio of 1:1-3, and reacting to obtain amino-substituted compound i.e. (1S,2S,6R,8S)-4-((R)-1-(1,1,1,3,3,3-hexamethyl-disilazan-2-yl)-3-methyl-butyl)-2,9,9-trimethyl-3,5-dioxa-4-bora-tricyclo(6.1.1.0(2,6))decane (III), (iv) dissolving (III) in an organic solvent, and carrying out deprotection in presence of trifluoroacetic acid or hydrochloric acid to obtain (R)-3-methyl-1-((1S,2S,6R,8S)-2,9,9-trimethyl-3,5-dioxa-4-bora-tricyclo(6.1.1.0(2,6))dec-4-yl)-butylamine (IV), (v) carrying out condensation reaction of (IV) with Boc-L- phenylalanine in presence of a condensing agent and an organic base to obtain (1-((S)-3-methyl-1-((1R,2R,6S,8R)-2,9,9-trimethyl-3,5-dioxa-4-bora-tricyclo(6.1.1.0(2,6))dec-4-yl)-butylcarbamoyl)-2-phenyl-ethyl)-carbamic acid tert-butyl ester (V), where the condensing agent is 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, 1-hydroxybenzotriazole, 2-(7-aza-1H-benzotriazole-l-yl)-1,1,3,3,tetramethyluronium hexafluorophosphate and/or benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate, and the organic base is triethylamine and/or diisopropylethylamine, (vi) dissolving (V) in an organic solvent, and carrying out deprotection in presence of trifluoroacetic acid or hydrochloric acid to obtain 2-amino-N-((S)-3-methyl-1-((1R,2R,6S,8R)-2,9,9-trimethyl-3,5-dioxa-4-bora-tricyclo(6.1.1.0(2,6))dec-4-yl)-butyl)-3-phenyl-propionamide (VI), (vii) carrying out condensation of (VI) with pyrazine-2-carboxylic acid in presence of a condensing agent and an organic base to obtain pyrazine-2-carboxylic acid (1-((S)-3-methyl-1-((1R,2R,6S,8R)-2,9,9-trimethyl-3,5-dioxa-4-bora-tricyclo(6.1.1.0(2,6))dec-4-yl)-butylcarbamoyl)-2-phenyl-ethyl)-amide (VII), where the condensing agent is 2-(1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, 1-hydroxybenzotriazole, 2-(7-aza-1H-benzotriazole-l-yl)-1,1,3,3,tetramethyluronium hexafluorophosphate and/or benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate, and the organic base is triethylamine and/or diisopropylethylamine, and (viii) removing pinanediol protecting group of (VII) under action of isobutylboronic acid, and recrystallizing with an organic solvent to obtain bortezomib, where the organic solvent is ethyl acetate, dichloromethane, diisopropyl ether, methyl tert-butyl ether, n-hexane and/or other organic solvents. The stirring time in the step (i) is 12 hours.