I've read entire Chapter 14: Organometallic Compounds of Francis Carey's "Organic Chemistry" but I still didn't get an answer to my question.
Quote from the book:
Because of their basicity organolithium compounds and Grignard reagents cannot be prepared or used in the presence of any material that bears a $-OH$ hydroxyl group.Nor are these reagents compatible with $-NH$ or $-SH$ groups, which can also convert an organolithium or organomagnesium compound to a hydrocarbon by proton transfer.
Fine. No arguments with that.
Terminal alkynes also give alkanes with Organolithium and Organomagnesium compounds.
Must be true if he says so. Now coming to the point,
- Ammonia and Amines have pKa around 36.
- Terminal alkynes have pKa of 25.
- Aldehyde pKa = 17, Ketone pKa = 19 and an Ester pKa = 25
- Water & Alcohos have pKa of 15-18.
If organolithium compounds and Grignard reagents act like bases with alcohols, terminal alkynes and amines/ammonia. Why do they act like nucleophlies and give addition reaction with carbonyl compounds? Why don't they act as bases and give alkanes instead? What am I missing here?