Isopulegol undergoes Prins cyclization reaction in the presence of 20 wt% of acid-treated montmorillonite K10 to produce octahydro-2H-chromen-4-ols in good yields and with high cis selectivities under solvent-free conditions. The solid-acid catalyst can be reused without loss of its activity.

Abstract(–)‐Isopulegol undergoes Prins‐arylthiolation with different aldehydes and cyclohexanone in the presence of HBF4·OEt2 to generate a library of 4‐arylthiooctahydro‐2H‐chromene derivatives in good to excellent yields with moderate to high cis selectivity at ambient temperature in dichloromethane. Readily available HBF4·OEt2 as a catalyst outshines CF3CO2H, which is generally used in excess amounts in Prins cyclization and domino Prins‐arylthiolation reactions.

No abstract

An efficient method has been developed for the synthesis of two new classes of tetrahydropyran derivatives comprising amide, tetrazole or benzothiazole moieties via a three-component reaction of 6-methylhept-5-en-2-ol, arylaldehydes and nitriles/thiols in the presence of a tetrafluoroboric acid diethyl ether complex. The reaction proceeds via the formation of an oxocarbenium ion. This protocol is highly diastereoselective and only single diastereomer has been isolated in each case.