Oxiranes and Oxirenes: Monocyclic

Metal‐Free Ring‐Opening of Epoxides

“…[108] developed a metalfree catalytic system for the hydrolysis of spiro-epoxyoxindoles (250). Here they explored the catalytic ability of a nitrogen-rich sulfonated carbon as a catalyst derived from a cucurbit [6]uril (CB 6 ) based molecule. Most of the spiro-epoxyoxindoles substrates underwent a smooth and clean ring opening to afford the corresponding vicinal diol product (251) with good to excellent yields (94-97 %) except the substrates having withdrawing groups which gave slightly less yield (82-86 %).…”

“…As a result, epoxides serve as excellent starting materials in various chemical reactions, allowing chemists to create a wide range of 1,2difunctionalized products. [4][5][6][7][8][9][10] By leveraging the reactivity of epoxides and using them as key building blocks, researchers have developed novel pharmaceutical compounds such as (R)-Denopamine ( 1), (R)-Pronethalol (2), Bubropian (3), Synerphrine (4),Brephedrine (5), Muricaticin (6), Hydrazidomycin (7,8), Dounomycin A (9), Neomycin A (10), and Bestatin (11) etc. (Figure 1)that potentially revolutionized the various industries and benefited human health.…”

“…This characteristic is attributed to the strain present in their small three‐membered ring, [1–3] which makes them highly reactive. As a result, epoxides serve as excellent starting materials in various chemical reactions, allowing chemists to create a wide range of 1,2‐difunctionalized products [4–10] . By leveraging the reactivity of epoxides and using them as key building blocks, researchers have developed novel pharmaceutical compounds such as ( R )‐Denopamine ( 1 ), ( R )‐Pronethalol ( 2 ), Bubropian ( 3 ), Synerphrine ( 4 ),Brephedrine ( 5 ), Muricaticin ( 6 ), Hydrazidomycin ( 7 , 8 ), Dounomycin A ( 9 ), Neomycin A ( 10 ), and Bestatin ( 11 ) etc .…”

Recent Advances in Greener and Energy Efficient Alkene Epoxidation Processes

“…In the presence of an aqueous base, the nucleophile (H 2 O) attacks the least substituted carbon atom based on an SN 2 -like reaction leading to ring-opening of the epoxide, whereas in the aqueous acid solution, the more substituted carbon is the site of nucleophilic attack according to the SN 1 displacement mechanism [59]. Similarly, epoxides undergo cleavage of the ether bond in the presence of anhydrous acids including HCl, HI, HBr to form halohydrin in the SN 1 -or SN 2 -like reactions, depending on whether the carbon attacked by the halogen anion is a primary, secondary or tertiary carbon [60,61].…”