M.Sc. (Semester IV) (CBCS) Examination Nov/Dec-2018
Organic Chemistry
STEREOCHEMISTRY
Time: 2½ Hours
Max. Marks: 70
Instructions: Attempt in all five questions. Section I (question is compulsory. Attempt any two questions from Section II and any two questions from Section III. Answer to all five questions (from Section II, III) should be written in the one and same answer book. All questions carry equal marks. Figures to the right indicate full marks.
SECTION I
Q.1

Answer the following
07
Define spiro compounds?
What is positional isomerism?
What is dipole rule or Van Arkel rule?
What is ring flipping phenomenon in cyclohexane?
What is chiral synthesis?
Define asymmetric synthesis?
What is chiral reagent?
B)Predict the product with stereochemistry.
07
SECTION II
Q.2
Discuss relative reactivity of distereomers in neighboring group participation?
07
Explain stability of cis and trans decalin and comment on their various physical properties.
07
Q.3
Explain different isomers of perhydroanthracene and comment on its stability and chirality?
07
Define stereoselective reaction? Explain stereoselectivity of epoxidantion with mCPBA and vanadyl reagent?
07
Q.4
What is enantioselective synthesis? Explain enantioselective synthesis via hydrazones?
07
Define stereospecific and regioselective reaction? Why hydroboration of alkenes is stereospecific and regioselective reaction?
07
SECTION III
Q.5
Define chiral catalyst? What is sharpless asymmetric dihydroxylation?
05
Explain Curtin Hammett Principle with examples?
05
What is difference in the distereomers stability of Stilbene dibromide and Tartaric acid?
04
Q.6
Explain Enatiotopic and diastereotopic atoms, groups and faces?
05
Explain stereochemistry of Allenes and biphenyl compounds.
05
What is Van-Auwers-Skita Rule? Explain physical properties of ortho, meta and para dimethyl cyclohexane?
04
Q.7
Write notes on any three:-
14
Distereiselectivity in aldol reactions
Optical purity and enantiomeric excess
Hydroboration by Ipc2BH and IpcBH2
Concept of I-strain