Acylative Dimerization of Tetrahydrofuran Catalyzed by Rare‐Earth Triflates

Abstract

Ytterbium, scandium, and lanthanum triflates catalyze the cleavage reactions of cyclic ethers to give various products. Most notable was the acylative cleavage of tetrahydrofuran with acetic anhydride catalyzed by Yb(triflate) 3 to give the dimeric compound CH 3 CO 2 (CH 2 ) 4 O(CH 2 ) 4 OCOCH 3 in 69% yield.

Sulfamic acid as efficient and reusable catalytic system for the synthesis of pyrrole, furan, and thiophene derivatives

“…of its ease of setup, mild conditions, rapid reaction, selectivity, increased yields [14], high purity of products and low cost, compared with their homogeneous counterparts [15]. It has been used as an efficient heterogeneous acid catalyst for ketal formation or acetalization [16], deprotection of acetals [17], tetrahydropyranylation of hydroxy compounds [18], esterification of cyclic olefins with aliphatic acids under solvent-free conditions [19], the Beckmann rearrangement of ketoxime [20] in dried CH 3 CN, and transesterification of β-ketoesters in ionic liquid [21].…”

NH2SO3H–SiO2 as a new water‐compatible, recyclable heterogeneous catalyst for the synthesis of novel (α,β‐unsaturated) β‐amino ketones via aza‐Michael reaction

“…It is commercially available and is a very cheap chemical. Recently, it was shown that sulfamic acid has the potential for use as a substitute for conventional acidic catalytic materials owing to its ease of set‐up, mild conditions, rapid reaction, selectivity, good yield, high purity of products and low cost, compared to its homogeneous counterparts . Silica‐supported sulfamic acid is a heterogeneous counterpart of sulfamic acid and has many advantages over sulfamic acid, such as recyclability, easy separation of catalyst and products, long catalytic life and thermal stability.…”