Preparation of Polyfunctionalized Alkenes

The Michael addition of nih oalkanes to alkenes substituted with two elecbon-withdrawing groups at the a- and 3-positions provides a new method for the preparation of functionalized alkenes. Although reactions are not new, Ballini and coworkers have used this sbategy in the synthesis of polyfunctionalized unsaturated carbonyl derivatives by Michael addition of nih oalkanes to enediones as shown in Eqs. 7.124-7.126. Success of this type of reaction depends on the base and solvent. They have found that DBU in acetonihile is the method of choice for this puipose. This base-solvent system has been used widely in Michael additions of nitroalkanes to elechon-deficient alkenes (see Section 4.3, which discusses the Michael addition). ... 

The preparation of polyfunctionalized nitrocyclopropanes is of special interest and, recently, these molecules have been prepared, in a one-pot process, starting from bromonitromethane (46) and electrophilic alkenes (47) bearing two electron-withdrawing groups in a- and ()-positions as shown in Figure 2.14 (Ballini et al., 2003b). 

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