Question

1. Indicate the number of stereogenic centers in the below molecules using a star or other identifying symbol (do not assign the stereochemistry): 2. Designate the chirality at each stereocenter in the following molecules: Me 3. (a) Achiral molecules can be superimposed on their mirror image. True or False (b) All meso compounds may be regarded as achiral compounds. True or False

Answer 1

I A stereo centre or stereogenic contre is the Catom in the molecule which is bonded to four different groups. - stereogen rah centre. number of stereogenic centre = 1 O = Stevens Centre 2. So, number of stereogenic centres = [3] HO 4th group is on the plane, NA So, make it below the - plane by doing double interchange Le double them, @ © literchange O After doing double enterchange to make ④ group below the plane, ④ → ① ♥ 0 0 follows clockwise So, its designation is R1 CamScann

. Me OH 6 group is on the plane. So, do double interchange to make ④ below the plane double do interchange OROD 0-0- 0- 0 follows clockwise. so, et is R Non-superimposable minor eimages are Only formed by chiral molecules. (6) True] Meso composends are achiral because of zero net optical rotation. The two chiral centres in a meso compounds have equal and opposite specific rotation values resulting into zero optical station. So, they are considered achiral.