Visible light assisted introduction of fluorinated building blocks to amine scaffolds via cross-dehydrogenative couplings

Abstract

From the beginning, when synthetic chemistry began there has always been an endeavour to discover and create new organic methodologies in chemistry. However, as we come into the 21st century and our understanding of what’s possible in chemistry increases so does the realisation that the resources available are rapidly depleting. As such we have chosen to undertake and present the merging of “green” and new photocatalytic methodologies.

The opening chapter describes the preliminary investigation into the use of a photocatalysed cross-dehydrogenative coupling reaction to introduce nucleophilic fluorinated building blocks into the C1 position of an N-aryltetrahydroisoquinoline. To this extent, an effective method to introduce the dimethylfluoromalonate group has been reported with a high tolerance to electron neutral and electron withdrawing moiety’s obtaining good to high yields, and strongly electron donating groups achieving moderate yields.

In the second chapter, an investigation into introducing selectivity into fluorinated cross-dehydrogenative couplings. The reaction envisaged the use of an organocatalyst to introduce enantioselectivity in the reaction between 1-fluoroacetone and N-aryl tetrahydroisoquinoline. The reaction proceeded with good to excellent yields with a variety aryl groups. The use of a primary cyclohexane diamine catalyst resulted in a promising enantioselectivity, demonstrating that an environmentally friendly methodology can induce selectivity.

In the final chapter, an elegant methodology for the addition and subsequent desulfonylation of the 1-fluoronitrophenylsulfonyl methane. Both transformations are completed by the use of visible light in conjunction photosensitizer. The reaction proceeds with good to excellent yields, and moderate diastereoselectivities tolerating a variety of electronic effects on the tetrahydroisoquinolines.

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Identifiers

ORCID for Ramon Rios: orcid.org/0000-0002-3843-8521

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