[skp524]

Other than route 1 suggested by the solution of a textbook , I am thinking of if route 2 and 3 can also add a carboxylic acid to the starting compound. Can anyone give some suggestion (s) ?


P.S.
1. I forgot to add reagent in the 1st step of route 2, i.e. adding HBr to C=C bond.
2. In the 1st step of route 3, I propose to undergo this conversion at elevated temperature , so as to give thermodynamic product.

[Schrödinger]

3 : I think (not sure, because the usual reagent HCN is absent) cyanohydrin formation might come as a hindrance. Unwanted side reaction, probably.

2 : The Grignard reagent has a potential site where the R- of the Grignard might attack. The ketone group of one molecule has a good probability of being attacked by the alkyl group of another molecule. Perhaps protecting the ketone (acetal) might prove useful. Deprotect it later, ofcourse.

[opsomath]

Solution 1 is not correct. You need to protect the ketone with a thioacetal or acetal or something.

Solution 2 is okay, I think, though I don't have personal experience with those Gilman reagents.

Solution 3 is the best one.