Methylenetriphenylphosphorane → 3-Methylene-2-((3-pyridinyl)methyl)-1-azabicyclo[2.2.2]octane

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Reaction Steps

The saturated ketone intermediates, such as 2-((3-pyridinyl)methyl)-1-azabicyclo[2.2.2]octan-3-one, also present opportunities for derivatization. One example is the reaction with phosphorus ylids (Wittig and Homer-Emmons reagents) to give alkenes. These alkenes can subsequently be reduced to alkanes by catalytic hydrogenation, providing a means of producing 2-((heteroaryl)alkyl)-1-azabicycles with alkyl and substituted alkyl substituents at the 3-position of the azabicycle. Thus, by way of example, 2-((3-pyridinyl)methyl)-1-azabicyclo[2.2.2]octan-3-one reacts with methylenetriphenylphosphorane to give 3-methylene-2-((3-pyridinyl)methyl)-1-azabicyclo[2.2.2]octane. Hydrogenation of this alkene, for example, over palladium on carbon catalyst, yields 3-methyl-2-((3-pyridinyl)methyl)-1-azabicyclo[2.2.2]octane as predominantly the cis diastereomer.

Provenance & Evidence