Zeolite-Mediated Cyclization of an Epoxide-Containing Polyene

Abstract

The utility of zeolites as promoters for the cyclization of an epoxide-containing polyene has been investigated. Reaction of polyene 1 with oven-dried 4 Å molecular sieves (type A zeolite) proceeds efficiently to generate bicyclic alcohol 2 in a 90% isolated yield. The reaction is sensitive to a variety of factors, including solvent type, water content, and zeolite acidity. Reactivity is apparently due to the zeolite lattice, since alumina and silica either are unreactive or generate a complex mixture of epoxide ring-opened products. Compared to the aluminum-based Lewis acid Me2AlCl, the zeolite-promoted cyclization of 1 was a more facile reaction, providing excellent product recovery after filtration. These results indicate that zeolites represent a new class of promoters in biomimetic polyene cyclizations.

Zeolite NaY‐Promoted Monocyclization of Epoxy Polyene Terpenes: A Unique Route for the Direct Synthesis of Incompletely Cyclized Naturally Occurring Terpenols

“…The use of acidic zeolites or other porous materials for the cyclization of epoxy terpenoids is very limited in the literature. Sen and co-workers [20] have used the H-form of the small-pore zeolites A and ZSM-5 for the cyclization of suitable silyl-substituted epoxy polyenes. A moderate to good product selectivity was achieved.…”

Biomimetic Cyclization of Small Terpenoids Promoted by Zeolite NaY: Tandem Formation of α‐Ambrinol from Geranyl Acetone

“…The use of acidic zeolites in the cyclization of terpenoids is very limited in the literature. Sen and co-workers [12] have used the Hform of the small-pore zeolites A and ZSM-5, as promoters for the cyclization of epoxide-containing polyenes, with moderate to good product selectivity. It was postulated that cyclization is initiated at the opening of the zeolite pores, since the size of the substrates does not allow them to diffuse into the interior of the cages.…”

A Simple, Convenient, One‐Pot Synthesis of Dihydro‐azolopyrimidines, DFT Calculation, and NMR Determination by Using H‐Ferrierite Zeolite as Catalyst

“…RE exchanged Y zeolites are reported as effective catalyst in organic chemistry, petroleum industry, agriculture, and domestic water treatment, and their specificity in gas phase transformations is widely used in such industry . Many organic reactions such as cyclization, alkylation, polymerization , or preparation of nitroalkane occurred in gas phase or with reactants adsorbed within zeolite. Lately, there have been sundry reports on the utilization of acidic zeolites (HY) in macro‐lactonization , acetylation , and gem ‐diacetalization , as well as in the synthesis and application of the organic‐functionalized zeolite beta .…”