Drawing Cyclohexane and Decalins Drawing Cyclohexane parallel bonds

Drawing Cyclohexane and Decalins

Drawing Cyclohexane parallel bonds

equatorial bonds

axial bonds

equatorial bonds axial bonds

Numbering Cyclohexane

4 6 5 1 2 3 Start anywhere and number consecutive carbons.

Tetrahedral Carbons in Cyclohexane

1 tetrahedral carbon

2 tetrahedral carbon

3 tetrahedral carbon

4 tetrahedral carbon

5 tetrahedral carbon

6 tetrahedral carbon

4 6 5 1 2 3

Disubstituted Isomers of Cyclohexane

1 2 trans-1, 2 -diequatorial

and. . .

1 2 trans-1, 2 -diaxial

are conformational isomers of one another, and. . .

1 3 cis-1, 3 -diequatorial

and. . .

1 3 cis-1, 3 -diaxial

are conformational isomers of one another, and. . .

4 1 trans-1, 4 -diequatorial

and. . .

1 4 trans-1, 4 -diaxial

are conformational isomers of one another.

Chair Conformations of Cyclohexane

you get hold red bonds in a plane flip this carbon above the plane flip the other carbon below the plane the other chair conformation

6 1 4 5 2 number carbons in this conformation 3 number the same carbons in this conformation 5 6 1 2 3 4

6 1 4 5 2 C 4 is above the plane, while. . . 3 C 4 is below the plane. given the plane Cformed the plane 1 is below by carbons and 2, . . . 3, 5, and 6 C 1 is above the plane and. . . 5 6 1 2 3 4

6 1 4 5 2 axial bonds here, and. . . equatorial here. 3 1 axial bonds equatorial bonds herebecome. . . here 5 6 2 3 4

abo ve 6 4 5 below 2 3 above bel ow ow bel 1 Equatorial bonds alternate being above and below the axial bonds on a given carbon atom

and. . .

above 4 6 above 5 above 1 2 below 3 below axial bonds alternate being above and below the equatorial bonds on a given carbon atom.

Drawing Decalins

trans - Decalins B Start with a chair cyclohexane Add two vicinal equatorial bonds Complete a second chair cyclohexane Axial fusion bonds are diaxial to rings A and B. A

cis - Decalins Y Start with a chair cyclohexane Add two vicinal bonds: One equatorial; one axial Complete a 2 nd chair cyclohexane Ring fusion substituents are cis to rings A and B. A X B cis-Decalin 1 Substituent X is equatorial to ring A and axial to ring B while substituent Y is equatorial to ring B and axial to ring A.

cis - Decalins Start with a chair cyclohexane X Add two vicinal bonds: One axial; one equatorial Complete a 2 nd chair cyclohexane Ring fusion substituents are cis to rings A and B. A Y B cis-Decalin Conformation 2 Substituent X is now axial to ring A and equatorial to ring B while substituent Y is now axial to ring B and equatorial to ring A.

Y cis - Decalins cis - Decalin Conformation 1 X cis - Decalin Conformation 2 rotate clockwise 90 o X X Y Y Enantiomers but equal in energy

The End