Oxazaborolidinone-Catalyzed Diels-Alder Reactions

Significance

Corey and Yamamoto have each reported that oxazaborolidine activation by strong Brønsted or Lewis acids generates a highly reactive cationic boron species for the enantioselective Diels-Alder (DA) reaction of an array of coupling partners. The authors of the present study have shown that neutral oxazaborolidinone Lewis acids also effectively catalyze DA reactions of α,β-unsaturated ketones with a variety of dienes, including less reactive furan. Cycloadducts are generally obtained in high yields, diastereo-, and enantio­selectivities. Further, similar catalyst loadings (10 mol%) with respect to cationic oxazaborolidines can be used.