Do we have microsoft exchange on prem connector? and how can we achieve this
What type of requirements are you trying to fulfill - most people accomplish it through the AD connector: Integrating SailPoint with Active Directory
Hi @shaffusailpoint as exactly said by @adunker we are accomplishing it through the AD Connector… however, there are specific usecases/scenarios that need further customizations anyways it depends on your requirements, just check the link that referred by Alex and let us know if you need anything further, for sure we are glad to support/assist you 
Have a great one!
Regards,
Mustafa