MIRC reactions substrates

The cz5-aziridine substrate shows, as expected on the basis of this model, predominant formation of the trans-cyclopropane product. The starting materials for this MIRC reaction can readily be obtained from the aziridine esters by reduction to the corresponding aldehyde and a subsequent Knoevenagel reaction with malonate ester (Scheme 25) [34]. 

Bond constructions similar to those just discussed can be achieved using an alkylidene malonate which is tethered to an alkyl bromide [72]. Of particular interest in this context is the controlled potential reductive cyclization of 263. As illustrated, the method provides a reasonably facile and modestly efficient entry to cyclobutanes 264. Presumably, the process is initiated by reduction of the alkylidene malonate rather than the alkyl halide, since alkyl bromides are more difficult to reduce. The same substrate, when reduced with L-Selectride undergoes conjugate addition of hydride and a subsequent cyclization leading to the five-membered ring 265. The latter transformation constitutes an example of a MIRC reaction [71-73], a process which is clearly complementary to the... 

The reaction of vinylsulphonium salts (356) with active methylene functions also gives electrophilic cyclopropanes via the formation of an unstable ylid which undergoes proton shift to an intermediate 1,4-sulphonium betaine (375) followed by expulsion of dimethyl sulphide (equation 115) . In addition MIRC reactions of substrates with... 

A large number of MIRC ( Michael addition induced ring closure ) reactions lead from a,j8-unsaturated carbonyl or nitrile substrates to cyclopropylcarbonyl products. These reactions do not have allylic intermediates and are treated in Section 1.1.2. 

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