Organic Chem Question: Including multifidene, how many stereoisomers are represented by this constitution?

Question

 Multifidene has one 5-carbon ring with a double bond and a -CH=CHCH2CH3 coming off of one carbon and a -CH=CH2 coming off of another

The IUPAC name is (3S,4S)-3-[(1Z)-1-Buten-1-yl]-4-vinylcyclopentene but the picture is easily found online.

 

I noted 2 stereocenters and 2 double bonds that are able to have an EZ configuration but I still keep getting the question wrong, I'm not sure of the presence of any meso stereoisomers

Answer 1

Hi Yiu,

 

Since the 3- and 4- positions of the molecule are different, there will be 4 stereoisomers from those two centers: (3S,4S), (3S,4R), (3R,4S), (3R,4R). But don't forget about the (1Z)-1-butenyl side chain, which can have either the E- or Z- configuration. There should be a total of eight stereoisomers wth the same basic connectivity.

 

Jim Scripko