2,4,6-Trisubstituted 3,4-dihydropyrans from acetylene and ketones: deacetylation in the KOBu t /DMSO system

2-Acetyl-3,4-dihydropyrans bearing 2-, 4- and 6-positioned aryl and alkyl groups, available from acetylene and ketones, undergo easy deacetylation in the KOBu t /DMSO system (100 °C, 1.5 h) to give 2,4,6-trisubstituted dihydropyrans.