Chapter 7 - Structure and Synthesis of Alkenes
I.  Introduction
	Sometimes referred to as olefins - oil formers.
	sp2 hybridization - restricted rotation due to pi bonds
II.  Elements of Unsaturation
	general formula is CnH2n said to contain one unit of unsaturation
	cycloalkanes are also CnH2n
	number of units of unsaturation can be easily obtained from molecular formula but 	comparing the number of hydrogen in an unsaturated carbon to that of a saturated 	hydrocarbon (remember saturated HC is CnH2n=2
	The total deficiency of hydrogen atoms divided by 2 gives the units of unsaturation.
	How many units of unsaturation in C10H16?  6/2 = 3.
	CORRECTION FOR :
		halogen - count each halogen as a hydrogen oxygen - ignore
		nitrogen - subtract one hydrogen for each nitrogen
		nitrogen rule - number of H and N must be an even number
III.  Nomenclature
	A. Rules.
		1. Locate longest chain containing the complete double bond.
		2.  Number the chain such that the double bond occurs at the lower number.
			cycloalkenes are assume to be 1,2.
		3.  Place the lower of the two numbers directly in front of the parent alkene name
		4.   Two double bonds are called dienes, three -triene, four -tetraene etc. 
			in these cases the parent must contain the greatest number of double 	bonds
		5.  Proceed as in the naming of alkanes
	B.  Alkenyl radicals
		1. vinyl or ethenyl    2.  allyl or 2-propenyl   3.  methylene or methenyl
	C.  Naming Geometric Isomers
		1. cis-trans
			acyclic systems - must indicate cis and trans if structure is known
			cycloalkenes are assumed to be cis
		2. EZ convention
			assign priorities to each group attached to one of the carbons of the double bond.  Do the same for the other two groups.
		If the two higher priorities are on the same side = Z
		If the two higher priorities are on the opposite side = E
IV.  Stabilities of Alkenes - you review pp. 312.
	A. trans more stable than cis
	B.  trans-cycloalkenes only stable for cyclooctene and higher
	C.  Bredt's rule - can't have a double bond at a bridgehead carbon of a bridged 	bicyclic compound unless one of the rings contains eight carbons.
V.  Synthesis of Alkenes
	A.  Base Induced Dehydrohalogenation Reactions
	B.  Use of Bulky Bases
		LDA, t-BuOK, 
		1.  Very useful on those halides that are prone to substitution
			Primary halides
			Secondary halides
				a.  cycloalkyl halides
				b.  secondary halides - give Hofmann product (least 					substituted product because of steric effects. 
	C.  Vicinal Dihalides - Zn or NaI
	D.  Dehydration of Alcohols - good method
		1.  Examples
		2.  Mechanism