Orgo 6.18-6.20

many compounds can eliminate in more than one way, to give __. 
In most E1 and E2 eliminations where there are two or more possible elimination products, the product will be what?


This general principle is called __ and reactions that give the most usbstituted alkene are said to follow __.

Zaitsev's rule

True or False:
Eliminatiosn can also take place under second order conditions with a strong base present.

The rate of the elimination is proportional to the concentrations of both the __ and the __, giving a __. This is a __ process, with both the base and the alkyl halide participating in the __, so this mechanism is abbreviated __ for __.
True False

Most strong nucleophiles are also strong bases, and elimination commonly results when a strong base/ nucleophile is used witha __ such as a tertiary or hindered secondary alkyl halide. instead of attacking the baci side of hte hindered __, for example, methoxide abstracts a proton from one of hte methyl groups. ONE STEP

In the general mechanism of hte E2 reaction, a strong base abstracts a proton on a carbon atom adjacent to the one with the __. As the base abstracts a proton, a __ form s adn the the leaving group leaves. Like the Sn2 reaction, the E2 is a __ reaction in which bonds break and new bonds form at the same time, in a single step.

The order of reactivity of alkyl halides towards E2 dehydrohalogenation is found to be __.

This reactivity order reflects the greater stablilty of __. Elimination of a tertiary halide gives a more __ than elim of a secondary halide, which gives a more __ than a primary. 

The stabilities of the alkene products are reflected in the __, giving __ and __ that lead to highly substituted alkenes.

The E2 reation requires abstraction of a proton a carbon atom __. If tehre are two or more possibilities, __ may result. In most cases, __ predicts which of the possible products will be the major product: __

Key mechanism of E2

Like the Sn2 reaction, the E2 follows a __: bond breaking and bond formation take place simultaneousyl, adn the partial formaiton of new bonds does what?.

__ require specific geometric arrangements so tha tthe orbitals of the bonds being broken can __with those being formed and hte electrons can flow smoothly from one bond to another.

The geometric arrangemnet required by Sn2 is a __; with teh E2, a __ is needed.

E2 elim requires partial formation of a new __, with its parallel p orbitals in the TS. The electrons that once formed a C-H bond must begin to __ with the orbital the the __ is vacating. Formation of this new __ implies that these two sp3 orbitals must be __ so that pi overlap is possible as the H and halogen leave and hte orbitals rehybridize to the p orbitals of hte new pi bond.

When th hydrogen and the halogen are __ to each other, their orbitals are aligned.
This is called the __ conformation. When teh hydrogen and hte halogen __each other, their orbitals are once again aligned. This is called the __ conformation.

Of these possible conformations, the __ is most commonly seen in E2 reactions. The transition state for __ is staggered, with the base far away from the leaving group. In most cases, this transition state is __ than that of the __.

The transition stae for __ is an eclipsed conformation. In addition to the higher energy resulting from eclipsign interactions, the transition state suffers from __ between the __ and the __. To abstract the proton, the base must approach quite close to the __. In most cases, the __ is bulky and - charged, and the repulsion between the base and the leaving group raises the energy of the __.

Some molecuels are rigidly held in __ with a H and a leaving group in a __> Such compounds are likely to udnergo __ by a __.

The E2 is a __ reaction, because different stereoisomers of the starting material react to give different __ of the product. This __results from the  __ that is usually involved int eh E2.