The Alcan Inc. headquarters is seen in Montreal, Quebec, May 7, 2007. Alcan Inc. said on Tuesday it rejected an unsolicited $27.6 billion takeover offer from rival aluminum producer Alcoa Inc. (Christine Muschi/Reuters)Reuters - Alcan Inc. rejected on Tuesday an unsolicited $27.6 billion takeover offer from rival aluminum producer Alcoa Inc. , but the Canadian company said it was in talks with third parties.