the R3SiNTf2 silylating agent. The presence of a chiral substituent derivedfrom (−)-myrtenal on the silicon atom led to a Lewisacid, which efficiently catalyzes the Diels–Alder reaction of α,β-unsaturated esters. Although not yet preparatively useful, the enantiomeric excesses (up to 54%) were the highest ever reported for a chiral silicon Lewisacid.