Question

Please complete BOTH parts. Please be clear!

Part C. The constitution of ectocarpene-a volatile, sperm-cell-attracting material released by the eggs of the seaweed Ectocarpus siliculosus-is shown below. In ectocarpene, all of the C-C double bonds have cis geometric configurations and the chirality center has an (S) absolute con- figuration. Please draw a spatially accurate structural representation of ectocarpene. Condensed Formula Structural Formula CH,CH2CH=CH-CHCH=CHCH2CH=CHCH2 131

Answer 1

C.

structural formula HHHIR C- W

E.

The priority numbering and configurations are given below;

In the given two pictures, H(least prior atom) is point into the plane.

С н"TCH,он Br 2 / нс. н но.

But in next one H is pointing up.

он CH,OH

As per the rotation it should be R. But, since the H is pointing up, the configuration is inverted.

So configuration is S.