Chiral Brønsted Acid Catalyzed Cascade Alcohol Deprotection and Enantioselective Cyclization.

The protection-deprotection sequence is vital to organic synthesis. Here, we describe a novel catalytic cascade where a chiral Brønsted acid selectively removes ether protecting groups and catalyzes intramolecular cyclization in one pot. We tested three model substrates from our previous work and investigated the rate of deprotection through gas chromatography (GC) studies. This work builds on our stereoselective synthesis of lactones by streamlining our synthesis. It also opens the door for additional investigations into other catalytic cascade reactions using chiral Brønsted acid catalysts.

Stereoselective Desymmetrizations of Dinitriles to Synthesize Lactones.

Nitriles are important organic functional groups, allowing for installation of nitrogen in organic synthesis. The Pinner reaction transforms nitriles into esters via the imidate group, but in general has previously necessitated harsh acid conditions. This work builds on the utility of the Pinner reaction through a stereoselective desymmetrization of dinitriles to form γ- and δ-lactones in good yields and diastereoselectivites.