What was the reason the Israelites left Canaan and went to Egypt?

Because of famine (Genesis ch.46).It was part of God's plan, since Egypt would be the "iron furnace" (Deuteronomy 4:20) in which the Israelites would be smelted, removing the dross, and would grow into a nation ready to receive God's Torah.

See also the Related Links.

Link: Timeline

Link: The Exodus