Lewis Acid Mediated Cyclizations: Diastereoselective Synthesis of Six- to Eight-Membered Substituted Cyclic Ethers

Abstract

Cyclic ethers are widely abundant in natural products. Cyclic ether templates are also utilized in drug design and medicinal chemistry. Although the synthetic processes for this class of compounds have been studied extensively with respect to five- and six-membered rings, medium-sized cyclic ethers are synthetically more challenging due to a variety of factors. Herein, we report our results on the Lewis acid catalyzed synthesis of medium-sized cyclic ethers in a diastereoselective manner.

Synthesis of Seven Membered Oxacycles: Recent Developments and New Approaches

“…However, this strategy remains less explored when oxepanes and oxepenes are the synthetic target. [ 7 ] In fact, during the last two decades, few publications have used this strategy as the key step.…”

Eight-Membered Rings With One Oxygen Atom

“…183 Using the same starting materials 252 in the presence of a combination of p-toluenesulfonic acid (p-TsOH) (30 mol%) and scandium or dysprosium(III) triflates (10 mol%) afforded a mixture of tetrahydropyrans 254 and few examples of the corresponding oxocene derivatives 253 (Scheme 40). 184 Few examples of benzoxocenes 257 are obtained from aza-ene/Prins cyclization reaction of O-aminoaryl alkenols 256 with electron-deficient aryl aldehydes promoted by TMSOTf in DCE (Scheme 41). 185 Scheme 39…”

Tandem Denitrogenation Oxidative Coupling Reaction of Phenyl Vinyl Azides and Cyclic Ethers Under Metal‐Free Conditions

“…It is widely present in natural products and biologically active compounds and has received great attention. Ethers are used as anesthetics in medicine, and talaumidin drugs that inhibit cancer cells, natural products sesaminone, imidazolidine drugs that have analgesic effects, etc., which have five‐ and six‐membered cyclic ethers in the molecular structure of these drugs [3,4] . In addition, carbonyl groups are important conversion groups and they play a key role in organic chemistry, [5,6] and various other compounds can be easily prepared by chemical conversion methods.…”

“…Ethers are used as anesthetics in medicine, and talaumidin drugs that inhibit cancer cells, natural products sesaminone, imidazolidine drugs that have analgesic effects, etc., which have five-and sixmembered cyclic ethers in the molecular structure of these drugs. [3,4] In addition, carbonyl groups are important conversion groups and they play a key role in organic chemistry, [5,6] and various other compounds can be easily prepared by chemical conversion methods. Therefore, α-oxyalkyl ketones, as structural units with a wide range of applications which have attracted widespread attention in the field of chemical research.…”