Alkenes 1

All atoms in same plane except for these hydrogens on sp3 carbon. Shape All atoms in same plane except for these hydrogens on sp3 carbon. Alkenes, 6 coplanar atoms.

Arene shapes Planar ring structure. 12 atoms coplanar. Phenyl group, C6H5,, Ph Ph = C6H5

Pi bonds Energy

Nomenclature Z / E generalization of cis / trans Use R, S priorities to compare substituents on same carbon. High priority on same side, Z. Opposite, E.

Cis / Trans in Cycloalkenes For small rings normally have cis double bonds.

trans cyclooctene

Terpenes and the isoprene Rule A terpene is composed of isoprene units joined head to tail (the isoprene rule). This moleculehas additional cross links. Note that location of functional groups such as OH or double bonds is not addressed.

Vitamin A Four isprene units joined head to tail One cross link (non-head to tail) linkage.

Fatty Acids Animal fats and vegetable oils are both triesters of glycerol, hence the name triglyceride. Hydrolysis of a triglyceride in aqueous base followed by acidification gives glycerol and three fatty acids. Fatty acids with no C=C double bonds are called saturated fatty acid. Those with one or more C=C double bonds are called unsaturated fatty acids.

Fatty Acids The most common fatty acids have an even number of carbons, and between 12 and 20 carbons in an unbranched chain. The C=C double bonds in almost all naturally occurring fatty acids have a cis configuration. The greater degree of unsaturation, the lower the melting point. Triglycerides rich in unsaturated fatty acids are generally liquid at room temperature and are called oils. Triglycerides rich in saturated fatty acids are generally semisolids or solids at room temperature and are called fats.

Fatty Acids the four most abundant fatty acids