(Reuters) – Alibaba Group Holding Ltd, Chinas largest e-commerce firm, offered to acquire AutoNavi Holdings Ltd in a deal valuing the Chinese digital mapping and navigation firm at $1.45 billion. Alibaba has been trying to expand its product line-up to better compete with Chinese rivals Tencent Holdings Ltd and Baidu Inc, particularly on mobile devices. AutoNavi said on Monday that Alibaba had offered to buy the 72 percent of the company that it did not already own for $21 per American depository share. The offer represents a premium of 27 percent to AutoNavis Friday close of $16.54 on the Nasdaq.