OnTriggerEnter getting delay when object is moving?

When object is moving from pointb to pointc (note they are defined vector3 points in program) the OnTriggerEnter function do not work untill object reached at it's destination (pointc) and then enter in OnTriggerEnter function and move from pointb to pointd.

I want to move object from pointb to pointc but when object collide then it should stop moving and enter into the OnTriggerEnter function.

 function Start () {
  yield MoveObject(transform, pointB, pointc, 2.0);
 }


 function OnTriggerEnter (other : Collider) {
     pointd = Vector3(14.5,-16.306,28.6);
     MoveObject(transform, pointB, pointd, 3);
 }

 function MoveObject (thisTransform : Transform, startPos : Vector3, endPos : Vector3, time : float) {
 var i = 0.0;
 var rate = 2.0/time;
 while (i < 1.0) {
     i += Time.deltaTime * rate;
     thisTransform.position = Vector3.Lerp(startPos, endPos, i);
     yield; 
 }
 }