- Radical-mediated intramolecular β-C(sp3)-H amidation of alkylimidates: Facile synthesis of 1,2-amino alcohols
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A new radical-mediated intramolecular β-C(sp3)-H amidation reaction of O-alkyl trichloro- or arylimidates is reported. Various oxazolines were efficiently prepared from easily accessible alcohol starting materials. The trichloro-oxazoline products can be hydrolyzed under mild conditions to give valuable 1,2-amino alcohols. This amidation reaction exhibits a broad substrate scope and good functional group tolerance, and offers a powerful means for the C(sp3)-H functionalization of alcohols. Mechanistic studies suggest that a sequence of 1,5-HAT of an imidate radical, iodination and cyclization might be operative.
- Mou, Xue-Qing,Chen, Xiang-Yu,Chen, Gong,He, Gang
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supporting information
p. 515 - 518
(2018/01/19)
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- Process for preparing α-aminoalcohols
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Process for preparing an α-aminoalcohol of formula EQU1 wherein R represents hydrogen or alkyl of from 1 to 5 carbon atoms, which comprises contacting a compound of formula EQU2 wherein R has the same meaning as above, with an alcohol of formula R'-OH wherein R' represents benzyl or the group EQU3 in which R" and R"' are independently selected from hydrogen and alkyl of from 1 to 4 carbon atoms in an organic solvent, in the presence of a basic catalyst, at from about 140° to about 170°C., treating the obtained product of formula EQU4 wherein R and R' have the above meanings, with at least an equimolecular amount of a p-toluene-sulfonyl halide, at from about -5° to about 20°C. in the presence of a tertiary organic nitrogen-containing base and reacting in a closed system the resulting compound of formula EQU5 wherein R and R' are as above defined, with an excess of gaseous ammonia, in the presence of an inert organic solvent, at from about 95° to about 120°C. and recovering the resulting product as its acid addition salt.
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