α-Nitrogenated organolithium compounds from α-amidomethyl and α-aminomethyl sulfones
1997; Elsevier BV; Volume: 53; Issue: 13 Linguagem: Inglês
10.1016/s0040-4020(97)00166-x
ISSN1464-5416
AutoresDiego A. Alonso, Emma Alonso, Carmén Nájera, Diego J. Ramón, Miguel Yus,
Tópico(s)Synthetic Organic Chemistry Methods
ResumoAbstract Successive reaction of α-amidomethyl sulfones 7a,b, derived from primary amides, with n-butyllithium and primary alkyl bromides (CH2CHCH2Br, CH2CMeCH2Br, CH2CBrCH2Br, CHCCH2Br, PhCH2Br, ButO2CCH2Br) at −90°C yields, after hydrolysis, enamides 11. The same procedure applied to α-amidomethyl sulfones 7c,d derived from secondary amides and using different electrophiles [AcOD, D2O, EtI, CH2CHCH2Br, BunI, PhCH2Br, ButO2CCH2Br, ButCHO, PhCHO, (CH2)4CO, EtOCOCl, CH3COCl, PhCOCl] gives substituted α-amidomethyl sulfones 13. Representative compounds 13 are desulfonated (Na·Hg, Na2S2O4 or Mg-MeOH) affording the amides 15. Lithiated sulfones 13 are methylenated to the corresponding acyl enamines 16 or 17 with in situ generated chloromethylmagnesium chloride. Naphthalene-catalysed lithiation of α-aminomethyl sulfone 19 in the presence of electrophiles [ButCHO, PhCHO, Et2CO, Pr2iCO, (CH2)5CO, PhCOMe] at −78 to 0°C leads, after hydrolysis with water, to the expected aminoalcohols 20. The application of this method to α-amidomethyl sulfones 7c,d using electrophiles [ButCHO, PhCHO, Et2CO, (CH2)4CO, (CH2)5CO, PhCOMe, Me3SiCl] yields fuctionalised amides 22. Representative examples of compounds 22 were hydrolysed (HCl-EtOAc or CF3CO2H), reduced (LiAlH4) or cyclised (NaH) to give aminoalcohols 24, 25 or oxazolidinones 26, respectively.
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