1198768-69-2

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• 926-62-5 isobutylmagnesium bromide 
• 123-11-5 4-methoxy-benzaldehyde 

Relevant academic research and scientific papers

Enantiospecific Brook Rearrangement of Tertiary Benzylic α-Hydroxysilanes

The Brook rearrangement of simple, chiral tertiary benzylic α-hydroxysilanes is presented. The rearrangement followed by proton trapping is enantiospecific and proceeds with inversion of the configuration at the carbon center. Importantly, the [1,2]-Brook

Catalytic highly enantioselective alkylation of aldehydes with deactivated grignard reagents and synthesis of bioactive intermediate secondary arylpropanols

Because of the high reactivity of Grignard reagents, a direct, highly enantioselective Grignard reaction with aldehydes has rarely been disclosed. In this report, Grignard reagents were introduced with bis[2-(N,N′- dimethylamino)ethyl] ether (BDMAEE) to effectively deactivate their reactivity; thus, a highly enantioselective alkylation of aldehydes with Grignard reagents resulted from catalysis by (S)-BINOL-Ti(OiPr)2. It is thought that BDMAEE chelates the in situ generated salts MgBr2 from a Schlenk equilibrium of RMgBr and Mg(OiPr)Br from transmetalation of RMgBr with Ti(OiPr)4. The Mg salts can actively promote the undesired background reaction to give the racemate. The chelation definitely inhibits the catalytic activity of the Mg salts, suppresses the unwanted background reaction, and enables the highly enantioselective addition catalyzed by (S)-BINOL-Ti(OiPr)2. Consequently, the Mg salt byproducts were not removed, less Ti(OiPr)4 than RMgBr was used, and extremely low temperature was avoided in this catalytic asymmetric reaction in comparison with the research disclosed before. Various alkyl Grignard reagents were investigated in the asymmetric addition, and iBuMgBr resulted in the highest enantioselectivity, >99%. Furthermore, important intermediate secondary arylpropanols for chiral drug synthesis were effectively synthesized with high enantioselectivity, up to 97%, in one step.

Highly catalytic asymmetric addition of deactivated alkyl Grignard reagents to aldehydes

[Chemical Equation Presented] Generally used and highly reactive RMgBr reagents were effectively deactivated by bis[2-(N,N-dimethylamino)ethyl] ether and then were employed in the highly enantioselective addition of Grignard reagents to aldehydes. The reaction was catalyzed by the complex of commercially available (S)-BINOL and Ti(O'-Pr)4 under mild conditions. Compared with the other observed Grignard reagents, alkyl Grignard reagents showed higher enantioselectivity and they achieved >99% ee.