Question

20. Predict the product(s) for the following reaction. Ho' IV A) B) C)III D) Iv 21. Predict the product for the following reaction. + CH + enantiomer 0 IV A. I 22. B. I C II D. IV Predict the product(s) for the following reaction. 2. H,O OCH A. I B. II C.I D. IV

Answer 1

20)In acidic medium, protonation of epoxide oxygen,resulting oxonium ion which develops a carbocation transition state. More alkylated position of epoxide develops stable carbocation transition state than less substituted position of epoxide. In epoxide ring openigthe nucleophile preferentialy attacks stabilized carbocaton.As it is a SN2 reaction inversion of configuration occurs.So option (C) is correct

21) Peracetic acid reacts with double bond to form mixture of stereoisomers i.e enantiomers. So option(C) is true.

22)In basic medium, opening of epoxide is by SN2 mechanism.No carbocation transition state formation due to absence of acidic medium. Approaching nucleophile preferentially opens sterically less crowded or less substituted position.So option(D) is true.