SAO PAULO (Reuters) -Brazilian businessman Nelson Tanure has retained advisory firm Rothschild & Co. to conduct bank negotiations critical to his proposed bid for Latin America's largest petrochemical firm, Braskem ( BAK ), two people familiar with the matter told Reuters.

Tanure made an offer in late May to acquire conglomerate Novonor's controlling stake in Braskem ( BAK ), leading to exclusive discussions between the two parties.

Known for investing in companies undergoing financial restructuring, Tanure must also negotiate with banks holding Braskem ( BAK ) shares pledged as collateral for Novonor's outstanding debts, as well as with oil company Petrobras, Braskem's ( BAK ) second-largest shareholder.

Tanure and Rothschild declined to comment. Rothschild's engagement by the Brazilian businessman was first reported by newspaper O Globo.

In a recent interview with Reuters, Tanure said he had initiated talks with the banks and key players in the potential deal without yet detailing his offer. He also said he wants to retain Novonor as a minority shareholder and grant Petrobras an expanded role in Braskem ( BAK ).