Question

Please show how to solve these questions!

1 The most stable conformation of trans 3-ethyl-1-odocyclohexane is: 2. List the following carbocations in the order of their stability (most stable first and least stable last). 6630 3. Arrange the following bicyclic alkenes in order of increasing stablity (least stable to most stable). 4. Assign the R and/or S configuration to the chirality centers in the following compound a) 2R, 3R b) 25, 3R c) 2R, 3S d) 25, 35 1. Provide a synthesis for the product shown below. For full credit, show all reagents and intermediate compounds in your synthesis process. 4 points each step; 36 points total OH b.

Answer 1

1 . ethyl is a bulky group and the confirmation in which a bulky gp occupies the equitorial position is the most stable one as there is minimum repulsion in that case .

So in confirmation (1) both ethyl and I are at equitorial position , so it is most stable .

Hence option (a) is correct .

2 .Order of stability of carbocation is 3°>2°>1° .

A 3° carbocation is attached to 3 other carbons , 2° attached to two other and 1° to one another carbon atom.

Given structures have ,

1st have 1° carbocation.

2nd have 3° carbocation

3rd have 2° and 4th also 2° carbocation .

So , order of stability of the structures is ;

2nd >3rd=4th>1st structure .

So option (b) is correct .