I'd like to welcome you,
olly2323:, to the Chemical Forums, but I'm going to ask you to read the
Forum Rules{click}This is a learning forum, we like to help people help themselves. You'll have to arrive with some of the basics, and be able to respond to a hint. Can you start with something you've learned recently? You wanted to "add magnesium" , but
Babcock_Hall: suggests a Grignard reagent wouldn't work. Do you know what a Grignard reagent is, and how it works? Can you find out in your textbook or class notes? Its not likely you've been assigned a moderately advanced organic synthesis, without having had some prior instruction.