18.6: Reactions of Epoxides - Ring-opening - Chemistry LibreTexts
Under aqueous basic conditions the epoxide is opened by the attack of hydroxide nucleophile during an S N 2 reaction. The epoxide oxygen forms an alkoxide which is subsequently protonated by water forming the 1,2-diol product. If the epoxide is asymmetric the incoming hydroxide nucleophile will preferable attack the less substituted epoxide carbon.
18.5 Reactions of Epoxides: Ring-Opening - OpenStax
Many different nucleophiles can be used for epoxide opening, including amines (RNH 2 or R 2 NH) and Grignard reagents (RMgX). An example of an amine reacting with an epoxide occurs in the commercial synthesis of metoprolol, a so-called β-blocker that is used for treatment of cardiac arrhythmias, hypertension, and heart attacks.
Epoxide Ring Opening With Base – Master Organic Chemistry
2015年2月10日 — Epoxides undergo reaction with nucleophiles under basic conditions at the least substituted end of the epoxide. If a chiral center is at this carbon, its stereochemistry will be inverted. Nucleophiles that will add to epoxides include hydroxide ion (HO-) alkoxides, Grignard reagents, organolithium reagents, and LiAlH 4 (among others)
Epoxides Ring-Opening Reactions - Chemistry Steps
Epoxide Ring-Opening with Strong Nucleophiles. The ring-opening reactions of epoxides occur via S N 2 mechanism where the oxygen of the epoxide is the leaving group. The product contains an alkoxy group and therefore, an aqueous or mild …
9.6. Epoxide reactions | Organic Chemistry 1: An open textbook
The carbons in an epoxide group are very reactive electrophiles, due in large part to the fact that substantial ring strain is relieved when the ring opens upon nucleophilic attack. Epoxides are very important intermediates in laboratory organic synthesis, and are also found as intermediate products in some biosynthetic pathways.
Nucleophilic ring-opening of epoxides: trends in β -substituted ...
2018年5月28日 — A large variety of nucleophiles such as carbon, nitrogen, oxygen, halogen, and sulfur-containing nucleophiles have been employed successfully in the ring-opening reaction of epoxides. The reactions are dominated by the electrophilic nature of strained three-membered epoxide ring and generally afford β -substituted alcohols (Scheme 3 ).
Ring opening of epoxides with C -nucleophiles - Springer
2016年7月4日 — Ring opening of epoxides has been an area of interest for organic chemists, owing to their reactivity toward nucleophiles. Such reactions yield important products depending on the type of nucleophiles used. This review article covers the synthetic approaches (1991–2015) used for the ring opening of epoxides via carbon nucleophiles.
Reactions of Epoxides - Nucleophilic Ring Opening
Epoxides are unstable because of ring strain and are rather good electrophiles. A variety of nucleophiles including -OH, amines, Grignard reagents, NaCN, and alkoxides (NaOR). For example, treating ethylene oxide with NaOH followed …
18.6 Reactions of Epoxides: Ring-opening - Chemistry LibreTexts
Epoxides may be cleaved by aqueous acid to give glycols that are often diastereomeric with those prepared by the syn-hydroxylation reaction described above. Proton transfer from the acid catalyst generates the conjugate acid of the epoxide, which is attacked by nucleophiles such as water in the same way that the cyclic bromonium ion described ...
Ch16: SN2 type reactions of Epoxides - Faculty of Science
Reactive nucleophiles react with epoxides in an S N 2 type of reaction. Reactive nucleophiles are usually anions so the reaction conditions are essentially basic. Examples of such nucleophilic systems are : RMgX, RLi, RC≡CM, LiAlH4, HO-, RO-.