143746-27-4Relevant academic research and scientific papers
Enantioselective addition of dialkylzinc reagents to N-(diphenylphosphinoyl)imines catalyzed by β-aminoalcohols with the prolinol skeleton
Almansa, Raquel,Guijarro, David,Yus, Miguel
, p. 2828 - 2840 (2008/03/28)
Several β-aminoalcohols with the prolinol framework are shown to be very efficient catalysts for the enantioselective addition of dialkylzinc reagents to N-(diphenylphosphinoyl)imines. The use of 0.5 equiv of the catalyst leads to the expected addition products in good yields and with ee up to 94% in a reaction time of only 4 h at room temperature. This ee is the highest value reported so far using 0.5 equiv of an aminoalcohol as a promoter. High enantioselectivities are obtained in the addition of dialkylzincs to both aromatic and aliphatic imines. The amount of the catalyst can be reduced to 0.25 equiv with a slight decrease in the ee. A very interesting effect of the addition rate and temperature on the enantioselectivity was also observed.
Diastereoselective lithiation and substitution of (S)-N-benzylprolinol and rac-N-benzylpiperidine-2-methanol via the carbamate esters: Kinetic resolution by means of (-)-sparteine-mediated deprotonation
Weber,Schwerdtfeger,Froehlich,Goehrt,Hoppe
, p. 1915 - 1924 (2007/10/03)
The (S)-N-benzylprolinol carbamate (S)-8 is deprotonated by sec- butyllithium with the removal of the pro-R-H and the intermediate lithium compound 10 is trapped by several electrophiles. Complete ul-diastereotopos- differentation is achieved irrespective
