Multicomponent coupling-cycloaddition sequences

Multicomponent Coupling-Cycloaddition Sequences via Alkynone Intermediates 72... 

MULTICOMPONENT COUPLING-CYCLOADDITION SEQUENCES VIA ALKYNONE INTERMEDIATES... 

This new multicomponent cascade reaction can also be performed with a large variety of aryl halides, most favorably iodides (Scheme 7). The yields in this coupling-cycloaddition sequence are particularly high with the parent... 

Multicomponent Synthesis of Heterocycles by Coupling-Cycloaddition Sequences... 

One of the most appealing aspects of these multicomponent syntheses is the reactivity of the components. Often, the reaction sequence commences without the aid of external catalysts and still preserves selectivity. However, sometimes the reactive center is created in situ, which does require the assistance of an external catalyst. Transition metals, for instance, can be effectively used to induce reactivity, like in the synthesis of another viral protein inhibitor. The work of Garner and coworkers provided a new route to the core of a novel influenza neuramidase inhibitor in one pot [38]. The [C -I- NC -I- CC] coupling reaction proceeds via a metalated azomethine ylide by condensation of the amine 134 and aldehyde 132, which undergoes a [3 -l- 2] cycloaddition with activated dipolarophile 133 (Scheme 14.17). 

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