Is this article accurate and fair in saying that "the Syrian government dismissed a UN plan that would have left rebels in control of the east if al-Qaeda-linked jihadists agreed to leave"? Why did the government dismiss the plan?
Why did they do this? The following quote from the BBC article may help.
Foreign Minister Walid al-Muallem, who met the UN envoy to Syria on Sunday, called the idea a violation of "national sovereignty".
As you said, it would have left rebels in control of the east. Presumably the Syrian government doesn't want the rebels to be left in control of the east.