Hotel and nightclub mogul Sam Nazarian is buying a boutique hotel group in a deal that will give billionaire investor Ron Burkle a significant stake in the new company. Nazarian’s SBE Entertainment Group, based in Mid-Wilshire, is picking up New York-based Morgans Hotel Group for nearly $80 million, which amounts to $2.25 per share. After the takeover, SBE would be worth about $800 million.