Question

understand the 5 considerations of alkenes + strong auds. be able to cany out the mechanism when an alkene reacts with bromine at -18°C carry out the following mechanisms: ① alkene + Brz + H₂O alkene + HgOAQ +THE+ H2O (memorze the demercuration step w NaBH4 Ex. try reacting this alkene product for each veachou. under the two condihons above. Draw the major

Answer 1

AK Alkenes + Stoons and 2 SNt wie formation of Carbocation I l via formation of carbocation Alkene reamengmen to Wagner-Meenwein Roosendment A Ring expension (Rind contraction oxidation, (using strong and on like conc. HNO3) The Hearts Reaction of alkone with Brig at -7802 in Ho, so b re a. Det simple alkene ver Horse H +ho H act as с Hydratha 0 6 Hip x attack form opposite site equat chance & Not faround due to Hydration of Broin Br the act listina Br - In This reaction as a Nuebophle and Botact as Elecpophila → Anti-allack take place • Stabilety of Casbocation determine the major product re Like Br By ? more Man s less 819

(Page 2) on * b. Mercusation I Alrene in the presence of 120. in THP solvent Hotel to H Hg COAC)2) The Ho Snorr 26 tho ú Ohu Hglope) Mechanism the 002 DAE One Mercusiniumion H20 toho 1 OA HqCOA) MOOD) Anh Ha ante rigton) NaBHq Hi Na BH Demureuration IMY

Page 3] Ex vecution of the + Breton & H20 Abr Hydoated Dimes lon less Nucleophube mon & major product Hoon tn Br Br minor product Lago AC Ac Hon Ang bae) o nera Hote) June ACOH SH Demercoration with NaBH4 POH major
Bromination and Mercuration in aqueous medium follow similar mechanism by the formation of a cyclic 3-membered ring. Hydrated Br- ion is less nucleophilic to attack so water molecules preferably act as nucleophile.