Question

6.     3,4-Dimethylpent-1-ene has the formula
CH2 = CH-CH (CH3) -CH (CH3) 2
When pure (R) -3,4-dimethylpent-1-ene is treated with hydrogen on a catalyst of platinum, the product is (S) -2,3-dimethylpentane.

(a) Draw the equation for this reaction. It shows the stereochemistry of the reagent and the product.

(b) Has the chirality center retained its configuration during this hydrogenation, or has it been invested?

(c) The reagent is called (R), but the product is called (S). Does this name change imply a
change in the spatial arrangement of the groups around the center of chirality? So,
Why does the name change from (R) to (S)?

Answer 1

R)-3, 4-dimethyt pent -1-ene when +reated with hydrogen a catalyst of platinum, the produet is (s) -2,3 -dimethylpentane CH3 CH 3 Ha/Pt CH3 H2C CH3 CH3 CH3 )3,4-dimethylpent-1-ene (5)- 2,3-dimethylpentane The chirality eeter center (c-3 carbon) inverted from R) to (5) durina this bydrogemetion FoT the reagent FOT the product a Rotating anticlockwise S. So, tis Kotating clockwoise .. the groups priority Changes during hydroge rather than 5patial orangement the leant priority and Taup (Here hydrogen); Cicway fromn us So, it is R.