Thread: How does a terminal alkyne react in a Grignard reaction? Will the carbonyl carbon attack the terminal carbon?

The complete reaction is R-CtripleCH first reacting with CH3CH2MgBr then reacting with a ketone. If I understand your explanations, which were very helpful thank you very much, the reaction will be left with C2H6 and my final product; this may be confusing but I'll try, R-CtripleC with the keto group hanging off the terminal carbon. Eventually this is protanated to become a hydroxy group.

terminal atom of alkyne is nucleophilic, so it attacks electrophilic carbon atom (bonded to Mg) of Grignard reagent.

The ctrplebondC-H bond being sp the H is acidic so it will react with the carbon of the Grignard , much like the Grignard will react with any acidic H to make the parent alkane from which the Grignard was prepared.

For instance, the reaction of CH3MgBr with the terminal alkyne will result in production of CH4. The carbon of th Grignard reagent is a very powerful base and will abstract a proton when it can. And of what carbonyl carbon do you speak ?

Confusing question. Grignard reagents attack carbonyl groups not vice verse. Are you trying to form a Grignard reagent with a compound that contains a terminal alkyne? Are you adding a terminal alkyne to a Grignard?? - if so why is there a carbonyl???

Alkyl Grignard reagents take the proton from a terminal alkyne to give a alkynylmagnesium halide and an alkane. This alkynylmagnesium halide can subsequently add to a carbonyl group.