Epoxides, like bromonium ions and mercuronium ions, can be ring-opened with various nucleophiles. The stereochemistry of the product depends on if the ring-opening occurs under acidic or basic conditions. The following two reactions – ring opening of an epoxide with water – illustrate this effect. Explain why the outcome of the reaction changes under these two conditions and provide electron-pushing arrows to explain the mechanisms.
Epoxides, like bromonium ions and mercuronium ions, can be ring-opened with various nucleophiles. The stereochemistry of...
Notes: A ‘detailed’ mechanism should illustrate all intermediates, by-products, and electron-pushing arrows. The marking scheme is given for each question as a guide; It is subject to minor changes. In class, we learned how to synthesize epoxides from alkenes using meta-chloroperbenzoic acid (mCPBA). Epoxides, like bromonium ions and mercuronium ions, can be ring-opened with various nucleophiles. The stereochemistry of the product depends on if the ring-opening occurs under acidic or basic conditions. The following two reactions – ring opening of...
1. (10 marks the wol 1. (10 marks) The Wolff-Kishner reduction is a method to transform ketones into alkanes. An example is provided below. step 1 step 2 NH oh oh oh oon HẠN-NH, KOH/H20 A mechanism for the Wolff-Kishner reduction is proposed online at the following website: However, all steps and all electron-pushing arrows are not clearly illustrated in this mechanism. Propose a detailed mechanism with all electron-pushing arrows for both steps of the Wolff-Kishner reduction. Notice the first...
Question1: In acidic conditions epoxides can be protonated. Protonated epoxides can undergo ring opening in the presence of poor nucleophiles. In these reactions the nucleophile preferentially attacks the more substituted carbon atom of the epoxide, as shown in the example below. Explain why the nucleophile preferentially attacks the more substituted carbon atom of the epoxide in acidic conditions. OCH3 он CH3 H3C CH3 H3C minor product major product