Enantiomerically pure δ-heteroaryl substituted β-hydroxy-γ,δ-unsaturated α-amino acids were stereoselectively synthesized starting from (2R)-(+)-2,5-dihydro-3,6-dimethoxy-2-isopropylpyrazine (Schöllkopf's reagent) and suitable β-heteroaryl-α,β-unsaturated aldehydes. The stereocontrolled addition gave a mixture of two diastereoisomers whose configurations were assigned on the basis of spectroscopic data and the accepted model for aldol condensation of the Schöllkopf's reagent. Upon controlled hydrolysis the adducts were transformed into the corresponding methyl esters of δ-heteroaryl substituted β-hydroxy-γ,δ-unsaturated α-amino acids.
Stereoselective synthesis of delta-heteroaryl substituted beta-hydroxy-gamma,delta-unsaturated alfa-amino acids / G. Cremonesi, P. Dalla Croce, F. Fontana, C. La Rosa. - In: TETRAHEDRON-ASYMMETRY. - ISSN 0957-4166. - 17:18(2006), pp. 2637-2641. [10.1016/j.tetasy.2006.09.023]
Stereoselective synthesis of delta-heteroaryl substituted beta-hydroxy-gamma,delta-unsaturated alfa-amino acids
G. CremonesiPrimo
;P. Dalla CroceSecondo
;F. FontanaPenultimo
;C. La RosaUltimo
2006
Abstract
Enantiomerically pure δ-heteroaryl substituted β-hydroxy-γ,δ-unsaturated α-amino acids were stereoselectively synthesized starting from (2R)-(+)-2,5-dihydro-3,6-dimethoxy-2-isopropylpyrazine (Schöllkopf's reagent) and suitable β-heteroaryl-α,β-unsaturated aldehydes. The stereocontrolled addition gave a mixture of two diastereoisomers whose configurations were assigned on the basis of spectroscopic data and the accepted model for aldol condensation of the Schöllkopf's reagent. Upon controlled hydrolysis the adducts were transformed into the corresponding methyl esters of δ-heteroaryl substituted β-hydroxy-γ,δ-unsaturated α-amino acids.Pubblicazioni consigliate
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