Michael Addition of Nitroalkanes to Dimethyl Citraconate, with DBU as Base: An Unexpected, One-Pot Synthesis of Polyfunctionalized Carbonyl Derivatives

Roberto  Ballini; Luciano  Barboni; Giovanna  Bosica; Dennis  Fiorini; Maria Victoria  Gil

doi:10.1055/s-2002-34209

LETTER

Michael Addition of Nitroalkanes to Dimethyl Citraconate, with DBU as Base: An Unexpected, One-Pot Synthesis of Polyfunctionalized Carbonyl Derivatives

Roberto Ballini*^a, Luciano Barboni^a, Giovanna Bosica^a, Dennis Fiorini^a, Maria Victoria Gil^b
^a Dipartimento di Scienze Chimiche, Università, Via S. Agostino 1, 62032 Camerino, Italy
Fax: +39(737)402297; e-Mail: roberto.ballini@unicam.it;
^b Departamento de Quimica Organica Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain

Abstract

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Abstract

Michael addition of nitroalkanes to dimethyl citraconate, with DBU as base, allows the one pot formation of keto diesters. The reaction proceeds through an equilibrium form of the acceptor, followed by Michael addition of the nitroalkane and then, in situ Nef conversion.

Key words

DBU - Nef reaction - keto esters - nitroalkanes - dimethyl citraconate

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Referenzen

References

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Selected analytical data for the compounds 8h,i. 8h: IR: 3412, 1738 cm^-1; ¹H NMR (CDCl₃): δ = 1.3-1.6 (m, 6 H), 2.42 (bt, 2 H, J = 7.0 Hz), 2.56 (dd, 1 H, J = 16.6 and 6.7 Hz), 2.62 (dd, 1 H, J = 17.7 and 6.1 Hz), 2.68 (dd, 1 H, J = 16.5 and 6.4 Hz), 2.91 (dd, 1 H, J = 18.0 and 7.0 Hz), 3.2-3.3 (m, 1 H), 3.6-3.7 (m, 2 H), 3.65 (s, 3 H), 3.66 (s, 3 H); ¹³C NMR (CDCl₃): δ = 23.3, 25.2, 32.4, 35.1, 36.3, 42.7, 43.1, 51.9, 52.2, 62.5, 172.0, 174.1, 208.3; MS (EI, 70 eV)
m/z 278 (M⁺ + 4), 257, 243, 187, 170, 127 (100%), 69, 55, 41, 31. 8i: IR: 1741 cm^-1; ¹H NMR (CDCl₃): δ = 2.14 (s, 3 H), 2.56 (dd, 1 H, J = 16.8 and 6.3 Hz), 2.6-2.8 (m, 6 H), 2.96 (dd, 1 H, J = 18.6 and 6.6 Hz), 3.2-3.3 (m, 1 H), 3.65 (s, 3 H), 3.66 (s, 3 H); ¹³C NMR (CDCl₃): δ = 30.3, 35.5, 36.6, 36.8, 37.4, 43.6, 52.3, 52.7, 172.5, 174.5, 207.2, 207.4; MS (EI, 70 eV) m/z 259 (M⁺ + 1), 226, 187, 127, 99 (100%), 59, 43, 29.