Grignard

[nixon13]

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How do you know if a grignard will react with something?

 

[HoangDDS]

Using CH3CH2MgBr, is like using CH3CH2- + :Mg+Br . The partial negative charge on the CH2 is gonna want to attack something that is partially positive. This is usually the alkyl carbon bonded to halide, a ketone, an aldehyde, an oxide, an acyl halide, or an ester.

When gringard (ie. CH3CH2MgBr) reacts with epoxide or alky halide the product will be a primary alcohol.

When reacting with an aldehyde, you get a 2ndary alcohol (OH)

--reacting with a ketone, you get a teritary OH

--reacting with an ester or acyle chloride, you get a teritary OH (2equivalence of grinard is used, it's just so reactive towards the ketone intermediate that it reacts again to from the teritary OH)

 

[nixon13]

cool thanks!

 

[condoleezarice]

Grignards are very strong nucleophiles, which is why you can't have C-O sp2 bonds or alcohols on grignards because they'd react with themselves. There are good reaction roadmaps with grignards on wikipedia if you look.