With all this type of problem start by calculating the number of double bond equivalents.
see (Broken Link Removed)
So here the DBE = {(2x8+2)-(14-0)}/2
=4/2=2
The hydrogenation product tells the carbon structure
CH3-CH2-CH2-CH(CH3)-CH2-CH2-CH3
and so the unknown contains two double bonds or one triple bond
If ozonolysis gives us
O=CH-CH(CH3)-CH=O
plus ethanal
then the structure is
CH3-CH=CH-CH(CH3)-CH=CH-CH3
Which is two DBE.
The structure is only chiral if one double bond is Z and the other E.
So there are four possible structures:
(R)-2Z,5E-4-methylhepta-2,5-diene
(R)-2E,5Z-4-methylhepta-2,5-diene
(S)-2Z,5E-4-methylhepta-2,5-diene
(S)-2E,5Z-4-methylhepta-2,5-diene
7. An unknown compound, C8H14, is optically active. Hydrogenation of the unknown
yields 4-methylheptane. Ozonolysis of the unknown yields ethanol and 2-
methylpropandial. Suggest a structure for the unknown consistent with the above date.
please help
2 answers
I think I have the absolute configurations correct, but please check using a model.