Would it be wise for a young company that is growing quickly but still hasn't achieved profitability to attempt to issue bonds as a way to expand its working capital?

No, the company should seek other alternatives in order to raise capital, e.g. private equity investors.

Explanation:

Bonds are the cheapest way to raise capital, but they also require the company to pay some type of annual coupon. If the company hasn't been able to make a profit yet, where will it get the money in order to pay the coupons. It would be basically a Ponzi scheme since the company would have to use the proceeds from the bond issuance in order to pay interests, but what happens when they ran out of money?