Question

Draw the structure of (2S,3Z)-2-fluoro-3-hexene. Use bold or hashed wedges to indicate the configuration at stereogenic sp3 C atoms. To indicate the stereochemistry about double bonds, place the groups attached to the double bonds in appropriate positions with 120 degree bond angles. Don't use bold, hashed, or criss-cross bonds to indicate double-bond stereochemistry.

Answer 1

Drawing of (2S,3Z)-2-Fluoro-3-hexene.

i)Its an IUPAC name of compound.

ii) The name end with hexene (alkene) it means the longest straight chain of 6 C atoms with 1 C=C double bond. 3 indicate the position of double bond i.e.C=C double bond between C3 and C4 atom. Also 3Z indicate geometrical isomer of 3-hexene with equally prior group on same side of the plane along the C=C bond,

iii) 2-Fluoro indicate the presence of Fluorine as substituent at C2 atom od longest chain. S in 2S is the stereodescriptor for C2 atom.

Drawing S configuration: on C2 4 substituents with priority order are (highest to lowest) -F > -C=C- > -CH3 > -H.

Put lowest priority group –H so that it points away from observer. Then place highest priority group –F so that it points towards observer. Now place 2^nd prior group -C=C- next to highest prior group so that vision should trace a circle in anticlockwise direction. Hence the (S) configuration.

Finally structure of (2S,3Z)-2-Fluoro-3-hexene is,