Alkyl amines are widely available, and easily prepared in high enantiomeric purity. In addition the amino group (NH<sub>2</sub>) can be carried through multi-step syntheses in protected form, and enables straightforward purification. These features are well appreciated in the use of alkyl amines for the preparation of nitrogen-containing products. We are expanding the toolkit of reactions of alkyl amines by developing cross-coupling reactions via cleavage of their carbon–nitrogen bonds. Capitalizing on the robust methods to prepare enantiopure benzylic amines, we have developed stereospecific cross-couplings of benzylic ammonium salts to deliver highly enantioenriched diaryl and triaryl alkanes, as well as benzylic boronates. This method was the first example of either an enantioselective or stereospecific cross-coupling of a benzylic electrophile with an arylboronic coupling partner.<br/><br/>Recognizing the abundance of primary alkyl amines with unactivated alkyl groups (not benzylic, allylic, or strained), we have also developed cross-couplings of alkyl pyridinium salts. These reactions efficiently convert alkyl amine derivatives into alkyl arenes, and provide new opportunities for the use of amines in synthesis. Our method is the first example of the cross-coupling of an alkyl amine derivative in which the C–N bond is not electronically or strain-activated. We have also extended this chemistry to cross-couplings of benzylic pyridinium salts to enable transformation of benzylic amino groups to aryl or vinyl substituents. Our more recent work with new coupling partners and new classes of alkyl pyridinium salts will also be presented.

Deaminative cross-couplings via C–N bond activation

2019 Fall National Meeting

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