Enantioselective Bromocycloetherification by Lewis Base/Chiral Brønsted Acid Cooperative Catalysis

Enantioselective bromocycloetherification by Lewis base/chiral Brønsted acid cooperative catalysis.

A binary catalyst system for the enantioselective bromocycloetherification of 5-arylpentenols is described. The combination of an achiral Lewis base and a chiral Brønsted acid affords good enantioselectivities for the cyclization of Z configured 5-arylpentenols to form bromomethyltetrahydrofurans. The constitutional site selectivity is highly dependent upon the aromatic substituent and the conf...

1 Lewis Acid – Brønsted Base Catalysis

From the synthetic point of view, organic synthesis via catalytic processes offers many benefits. Catalysis frequently obviates the excessive use of the activating reagents and associated tedious purification processes, thereby offering more environmentally benign synthetic processes. Furthermore, the specific activation mode of a catalyst allows for highly chemoselective transformations that a...

Cooperative transition-metal and chiral Brønsted acid catalysis: enantioselective hydrogenation of imines to form amines.

Chiral amines are an integral part of numerous important bioactive compounds. This privileged structural motif is found in naturally occurring alkaloids and amino acid derivatives as well as in pharmaceuticals, herbicides, and insecticides. Typically, enantiomerically pure amines are key building blocks in the drug-discovery process, but they are also sold on a multi-hundred-ton-scale as kineti...

Enantioselective 1,3-dipolar cycloaddition of nitrones with ethyl vinyl ether: the difference between Brønsted and Lewis acid catalysis.

From designer Lewis acid to designer Brønsted acid towards more reactive and selective acid catalysis

This review focuses on the development of acid catalysis for selective organic transformations conducted in our laboratories for the past 30 years. Several important concepts in designing of catalysts are described with some examples. Further, recent developments in super Brønsted acid and their applications in a one-pot procedure to construct complex molecules with high diastereoselectivities ...