Study On The Hydrogen-Bond-Assisted Nucleophilic Addition And Tandem Reaction Of Acylsilanes

Due to its unique properties,the hydrogen bond plays a role of guiding the reaction in the organic reaction.The main research content of this paper is the hydrogen bond-assisted tandem reaction of nitroethanol and acylsilanes for the highly stereoselective synthesis of silyl enol ethers and the hydrogen bond-assisted nucleophilic reaction of acylsilanes and potassium allyl trifluoroborate in the aqueous solutions.The details are as follows:1.In the presence of phase transfer catalyst of n-Bu₄NCl and inorganic base Cs₂CO₃,tandem reaction of acylsilanes and nitroethanol was realized.With the aid of hydrogen bonds,high E/Z selectivity products of enol silyl ether（the selectivity of the Z configuration up to 99:1,and the selectivity of the E configuration up to 9.2:1）were obtained.According to the mechanism research and experimental results,we proposed the Henry reaction/Brook rearrangement/elimination and Henry reaction/Brook rearrangement/reverse Henry reaction/elimination process.2.The catalyst-free nucleophilic addition reaction of acylsilanes and potassium allyltrifluoroborate in water was developed,generating the unsaturatedα-hydroxysilanes with high yields.With the assistance of hydrogen bonds,the Brook reaction is effectively inhibited,and the addition reaction is efficiently realized.The reaction operation method is simple,the conditions are mild,and the substrate has an excellent broad spectrum,which conforms to the theme of green chemistry.