Question

so i understand that halogenation can only occur by anti addition. that being said how can you add 2 halogens to eachother in an anti fashion when the double bond is located on the substiturnt of a ring. this was a problem in my textbook and the answer key gave that answer. secondly hydroboration - oxidation can only occur by syn additon. so how can you add two atoms in syn two a substituent of a ring ? i dont understand because these answers have the same stereochemistry but one of the reactions can only occur in syn and one can inoy occur in anti

OH ha can only syn addhon occur Or2 ho Can an and addrian occus hu

Answer 1

م ا ا - BH₂ n.o NeoH در S syn addition syn addition simultaneously | is taking and no place on transition the same side state & na ring and formation

come to me Addition of Bra in allene, there Jenna By is a famation of both three membered ring then ring opening by another Be thorough cinti peri planer & back side attack to produce anti addition product. 1. The mojor fachon b ů the three membered ring which decades the stereochemistry here