We have prepared a series of novel 2,3-dihydro-4-pyridones containing boronate esters using the aza Diels-Alder reaction with Danishefsky's diene and imines derived from formylphenylboronic acids. This reaction can be carried out in moderate to high yields using Yb(OTf)(3) as a Lewis acid catalyst. Two new boron compounds exhibited moderate antifungal activity (at 100 mu g disk(-1)) using Amphotericin B as a control. (C) 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:56-63, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20512