If you want to build a modern enterprise application and want to go with a framework I'll suggest you to go with either Bootstrap or Foundation. You will have a great set of plugins/components to build complex UIs. And regarding JavaScript frameworks three names come to my mind :
We have had success with both Angular and Backbone in past. React is a little advanced, IMO. Also if you are going with Backbone then you may combine it with a framework like Marionettejs.