Question

1. Draw (1S,3S)-3-aminocyclohexanecarbonitrile structure below:

2. Draw the two chair conformations of the above disubstituted cyclohexane compound, before and after ring-flip.

3. Draw the Newman projections of both chair conformations about the C1−C6 and C3−C4 bonds.

4. Which conformation is the least stable one? Briefly explain your answer with words AND by showing it on the appropriate Newman projection.

Answer 1

0 1 (1S, 3S)-3-aminocyclohexane carbonitrile WHEN @ I-CN T H 2- ...(-63 I below, 234, Clockwis 03-...6-05 sols 4-H ONH₂ ( -NH2 0 2-....(2-4- 4 below 1-2 anti- 3- ---C4-25- clockwi 4- H so 35 3- ...6 PNO - domo so, the str. is a will NH₂ NH2 2 Chair Str. CN normal chair CN Invert chair 3 . H H - NHO 1 Huu HL sro H. N 12 | 1 | Hun NC It н projection of Normal chair Newnana projection of invert chair

① Among both conformation, invert chair conformation is least stable. Because, if nitrile group will stay in axial position, there will be a sterichindrances with 3 & 5 Hydrogen. I whereas in the normal Str. Alle group in even NH₂ gr. is in axial position, due to t-bonding interaction with C. & C5 Hydrogen, It this structure will gain extra stability. ayic It LH Hii ni NCH I HII TCN axial WH₂, group, str. gain extra stability by H-bonding interaction # H1 # H H NH2 iz axial C=N, str., least stable due to steric hindrance. CNAH H H Hb