An Environmentally Benign Synthesis of Octahydro-2H-chromen-4-ols via Modified Montmorillonite K10 Catalyzed Prins Cyclization Reaction

Abstract

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.

Acid‐modified Halloysite Nanotubes as a Stereoselective Catalyst for Synthesis of 2H‐Chromene Derivatives by the Reaction of Isopulegol with Aldehydes

“…It is known that compounds with a chromene (benzopyran) scaffold have a broad spectrum of biological activity . A high pharmaceutical potential and low toxicity of these substances resulted in a considerable interest in the synthesis of new chromene derivatives . Recently, it has been shown, that in catalytic condensation of a natural allyl alcohol (−)‐isopulegol (I) with aldehydes, substituted octahydro‐2 H ‐chromen‐4‐ol (III) as 4 R ‐ and 4 S ‐diastereomers was formed along with a dehydration product IV (Scheme ).…”

Sequential Oxidation-Prins Reaction Processes Induced by the Same Iron Salt: Direct Access to 2-Aryl-4-Chloro-Tetrahydropyrans from Benzyl ­Alcohols

“…Of interest, the beneficial role of the clay for the Prins reaction could not be totally excluded as demonstrated by two recent reports, which appeared during our investigations. 28 This sequential procedure 29 was then applied to different benzylic alcohols leading to different 2-aryl-4-chlorotetrahydropyrans in moderate to high yields (31-82%, Scheme 2). All the results are collected in Table 1.…”

First Example of a Four-Component Prins Cyclization Reaction: Diastereoselective Synthesis of Dithiocarbamate Derived Octahydro-2H-chromenes

“…The products were obtained as inseparable diastereomeric mixtures in all cases, and the disatereomeric ratios were determined by their 1 H NMR analysis. The stereochemistry of both diastereomers was assigned on the basis of our previous reports of synthesis of different 4‐substituted octahydro‐2 H ‐chromenes from (‐)‐isopulegol –. For example, the characteristic δ values in the 1 H NMR spectrum of the products 6 e / 7 e can be explained as follows: two characteristic protons i.e.…”