Question

PART OPTICAL ISOMERISM Stereocenters and Chirality Construct a model in which a central carbon (black) has four different groups directly attached (a single sphere each of white, red, green andble). Draw this in your lab notebook. 1. Does this molecule have a rotational axis of symmetry? 2 plae of symmetry? This molecule is said to contain a stereocenter (in view of the 4 different attached groups. Here this center provides the molecule with chirality ("handedness", a molecular property). Thus the carbon is sometimes said to have a chiral center, or an asymmetric center, (although these two terms are less accurate). Replace the green ball by a red one. 5. Does the molecule now possess symmetry? Describe any. 6. In view of 1-5 above, what conditions are necessary for a molecule to be chiral? 7. Draw formulas for each of the following and mark each stereocenter with an asterisk ) 2-bromobutane; 3-pentanol, 2- hydroxypentanoic acid; 2,3-pentanediol; 2,3-butanediol.

Answer 1

1,2 This molecule with four different group attac hed to the central atom does not have rotational axis of symmetry and also does not have plane of symmetry 5 By replacing green ball with red ball, the molecule possess plane of symmetry which can disect the m olecule into two half 6 The condition for the molecule to be chiral is that the molecule shold not possess any element of symmety он он он он OH он Chiral symmetrical Chiral Chiral Chiral, except me so fomm Only one Question is allowed