Schwesinger’s superbases are important nonmetallic non-ionic organic superbases with strong alkaline and low nucleophilicity. Schwesinger’s superbase t-Bu-P4 exhibits high reactivity toward the activation of silylated pronucleophiles, deprotonative reactions and polymerizations. In this paper, t-Bu-P4 was used successfully to activate N,N-dimethyl carbamoylsilane and (perfluoroalkyl)trimethylsilane to initiate the nucleophilic addition reactions of aldehydes and ketones, respectively, affording the corresponding amide derivatives and perfluoroalkyl carbinols.
1. Amide and its derivatives are important structural units that constitute protein and polypeptide compounds, which synthesis of polysubstituted amide derivatives is of great significance to the synthesis of drugs and the synthesis of important natural products. We developed organic superbase-catalyzed aminocarbonylation of N,N-dimethyl carbamoylsilane with α,β-unsaturated ketones. Under the catalysis of 10 mol% Schwesinger’s superbase t-Bu-P4, a variety of enones and ynone reacted with N, N-dimethyl carbamoylsilane to afford α-siloxyamides or α-hydroxyamides in 56-82% yields. Finally, based on the previous studies on t-Bu-P4 catalyzed reactions of silylated reagents, a plausible silicon activation mechanism was proposed.
2. Organofluorine compounds have unique physical, chemical and biological activities. Similar with the pentafluoroethyl and trifluoromethyl, however, pentafluoroethyl exists unique physical properties and biological activities, including bigger steric hindrance, stronger electron-withdrawing, higher lipophilicity and greater stability. Whereas, methods to add the pentafluoroethyl group into organic compounds are limited. Organic superbase-catalyzed nucleophilic addition reactions of TMSCF2CF3 and TMSCF3 with aldehydes and ketones, respectively, have been described in the paper. Under the catalysis of 10 mol% t-Bu-P4, (perfluoroalkyl)trimethylsilane undergo direct nucleophilic addition reactions with aldehydes and ketones to afford the corresponding perfluoroalkylation adducts in 30-98% yields. At last, based on the pioneering work , we proposed a plausible mechanism.
In summary, organic superbase-catalyzed nucleophilic addition reactions of silylated reagents with aldehydes and ketones has been developed. The simple procedure, transition-metal-free and extremely mild conditions provide a novel method for the introduction of amide and perfluoroalkyl group to the carbonyl compounds.
谷歌
火狐
