Organic Chemistry

466 CHAPTER 12 Reactions of Alcohols, Ethers, Epoxides, and Sulfur-Containing Compounds

PROBLEM 27

Finding that mustard gas interfered with bone marrow development caused chemists to

look for less reactive mustard gases that might be used clinically. The following three

compounds were studied:

One was found to be too reactive, one was found to be too unreactive, and one was found

to be too insoluble in water to be injected intravenously. Which is which? (Hint:Draw

resonance contributors.)

12.11 Organometallic Compounds

Alcohols, ethers, and alkyl halides all contain a carbon atom that is bonded to a more

electronegative atom. The carbon atom, therefore, is electrophilicand reacts with a

nucleophile.

But what if you wanted a carbon atom to react with an electrophile? For that, you

would need a compound with a nucleophilic carbon atom. To be nucleophilic, carbon

would have to be bonded to a less electronegative atom.

A carbon bonded to a metal is nucleophilic because most metals are less electroneg-

ative than carbon (Table 12.3). An organometallic compoundis a compound that

contains a carbon–metal bond. Organolithium compoundsand organomagnesium

compoundsare two of the most common organometallic compounds. The electrostatic

potential maps show that the carbon atom attached to the halogen in the alkyl halide is

an electrophile (it is blue-green), whereas the carbon atom attached to the metal ion in

the organometallic compound is a nucleophile (it is red).

CH 3 Cl CH 3 Li

electrophile

less electronegative

than carbon

nucleophile

CH 3 CH 2 + E+ CH 3 CH 2 + M+

δ− δ+

ME

CH 3 CH 2 + Y− CH 3 CH 2 + Z−

δ+ δ−

ZY

electrophile nucleophile

more electronegative

than carbon

CH 3 HC N

O CH 2 CH 2 Cl

CH 2 CH 2 Cl

N

CH 2 CH 2 Cl

CH 2 CH 2 Cl

N

CH 2 CH 2 Cl

CH 2 CH 2 Cl

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