Please answer and explain 1. How are we able to determine whether the addition o
ID: 228816 • Letter: P
Question
Please answer and explain
1. How are we able to determine whether the addition occurred via syn-addition or anti-addition?
a) We cannot determine the between the enantiomeric products as enantiomers possess the same melting point.
b) We cannot determine the difference between the diastereomer products as diastereomers possess the same melting point.
c) We are able to determine how the addition occurred based on melting point as diastereomers possess different melting points. If the melting point is around 93-95°C, then the addition occurred via anti-addition. If the melting point is around 200-205°C, then the addition occurred via syn-addition.
d) We are able to determine how the addition occurred based on melting point as diastereomers possess different melting points. If the melting point is around 93-95°C, then the addition occurred via syn-addition. If the melting point is around 200-205°C, then the addition occurred via anti-addition.
2. Which type of addition is more likely to occur? Why?
a) Anti-addition is more likely to occur as an intermediate bromonium ion occurs, causing too much steric hindrance for the second bromine to add on the same face as the first.
b) Both anti-addition and syn-addition are equally likely to occur.
c) Syn-addition is more likely to occur as two bromines naturally always add on the same side.
d) Syn-addition is more likely to occur as everything in chemistry always adds in a syn manner.
3. Which diastereomer result from anti-addition and which results from syn-addition? State the R/S configuration for each.
a) Anti-addition yields the erythro product (RR or SS enantiomers), while syn-addition yields the threo product (RS or SR enantiomers).
b) Anti-addition yields the erythro product (SR or RS enantiomers), while syn-addition yields the threo product (SS or RR enantiomers).
c) Syn-addition yields the erythro product (SR or RS enantiomers), while syn-addition yields the threo product (SS or RR enantiomers).
d) Syn-addition yields the erythro product (RR or SS enantiomers), while syn-addition yields the threo product (RS or SR enantiomers).
Explanation / Answer
1) option D is the answer
because the syn addition leads to form unstable product than the anti addition. In syn addition the adding elements are in same side but its in opposite for the anti, thats why the difference in stability and the syn products will melt fast than anti
2) option A
as i say adding on the same side willl lead to more steric hinderance, so anti addition is more favorable
3) option A is the answer
anti addition always leads RR , SS and syn leads RS , SR as it is in the option