A direct method for the synthesis of polyfunctionalized unsaturated carbonyl derivatives by Michael addition of nitroalkanes to enediones with the help of DBU
作者:Roberto Ballini、Giovanna Bosica
DOI:10.1016/0040-4020(95)00136-v
日期:1995.4
The Michael addition of several nitroalkanes to dimethyl maleate, (Z)-3-hexene-2,5-dione, N-ethyl maleimide, and N-phenyl maleimide, in MeCN or THF, proceeds very efficiently on DBU as base, and furnishes good to high yields of polyfunctionalized unsaturated carbonyl derivatives.
A New, One Pot Synthesis of Alkylated Methyl Tri- and Tetracarboxylate Derivatives by Nitrolkanes
作者:Roberto Ballini、Giovanna Bosica、Dennis Fiorini、Maria Victoria Gil、Alessandro Palmieri
DOI:10.1055/s-2004-815948
日期:——
The reaction of nitroalkanes with trimethyl trans-aconitate in acetonitrile, in the presence of DBU as base, allows the one pot formation of alkylated methyl tri- and tetralkanoate derivatives via base induced nitrous acid elimination. The title compounds can also be obtained, in one flask, starting with the reaction of methyl nitroacetate with dimethyl maleate, followed by the addition, in the same flask of the nitroalkane.
Conjugated addition of primary nitroalkanes to α,β-unsaturated ketones or α,β-unsaturated esters, in the presence of two equivalents of DBU, allows the one-pot prepration of γ-diketones or γ-keto esters, respectively. When 2-aryl-1-nitroethane derivatives are employed as starting nitroalkanes in the reaction with α,β-unsaturated ketones, the one-pot formation of cyclopentenones is observed.
Michael addition of nitroalkanes to dimethyl maleate with DBU. A new direct method for the synthesis of polyfunctionalized α,β-unsaturated esters
作者:Roberto Ballini、Alessandro Rinaldi
DOI:10.1016/0040-4039(94)88479-x
日期:1994.12
Michael addition of nitroalkanes to dimethylmaleate, in acetonitrile and with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as base affords, directly, polyfunctionalized α,β-unsaturated esters, via elimination of nitrous acid
Progress in the Synthesis of the Lituarines: Stereocontrol in Sequential C−C Bond Formation on a Spirobutenolide Template
作者:Jeremy Robertson、Jonathan W. P. Dallimore
DOI:10.1021/ol0520018
日期:2005.10.1
[GRAPHICS]We describe elaboration of a tricyclic spirobutenolide corresponding to the C(7-18) tricyclic substructure common to lituarines A-C. Conjugate addition, to install the C(16) methyl, is followed by construction of the crucial C(18-19) bond by silyl enol ether addition to the derived spiroacetal C(18)-O oxonium ion. Esterification with a C(1-6) acid, and selective ozonolysis to release the C(23) carbonyl, complete the assembly of all the carbons present in the lituarine macrocyclic core.