Allen & Overy (A&O) and Wachtell Lipton Rosen & Katz are among a line-up of firms advising on Walgreen’s $6.7bn (£4.3bn) acquisition of a 45% stake in Alliance Boots, a tie-up that will create a global pharmacy giant with more than 11,000 stores in 12 countries.

Wachtell and A&O are both advising the US pharmacy chain, which plans to complete a full merger with Alliance Boots in three years for a further $9.5bn (£6bn), as well as the assumption of the retailer’s then outstanding debt.