Enantiospecific Synthesis of Alkylboronate Esters Enabled by Carbopalladation of C─C σ-Bond and Novel Tsuji–Trost-Type Allylations

• Applicant: Dr. Hui Wang
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2020 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 442129649

Chiral boronic acids and related derivatives are highly valuable building blocks in stereoselective organic synthesis because of the multitude of asymmetric transformations that they can undergo. Due to the tremendous potential of boron chemistry, our aim here is to develop new and different reactions that enable us to synthesize novel and valuable chiral boron-compounds. Aggarwal group has made remarkable progresses in lithiation-borylation and assembly-line synthesis of chiral boron-compounds and natural products. The unprecedented distal cross-coupling reaction via carbopalladation of C–C σ-bonds (using a ring-strain strategy) by Aggarwal et al. opens up a new direction in organoboron chemistry. In this regard, developing an efficient catalytic metalate-shift-based transformation to enable C─C σ-bond carbopalladation in less strained substrates is highly desirable. Meanwhile, the Tsuji-Trost reaction utilizing a racemic α-halo allyl boronic ester also provides great opportunities for the synthesis of enantioenriched alkyl boronate esters. In this research, we will investigate and design more general and less strained substrates to accomplish catalytic ‘conjunctive’ cross-couplings and synthesize a wide range of racemic α-halo allyl boronic esters to achieve Tsuji-Trost reactions with different nucleophiles. We envision that these transformations can provide new opportunities for the construction of chiral alkyl boronic ester building blocks for use in asymmetric synthesis.

• DFG Programme: Research Fellowships
• International Connection: United Kingdom
• Host: Professor Varinder Kumar Aggarwal, Ph.D.