ASP.NET Core Virtual directory in IIS Express

i created two aspnet core web and api projects under one solution using VS2015

src
|
|-app.web
|  |-localhost:29999/
|  |-startup.cs 
|  
|-app.api
   |-localhost:29999/api/
   |-startup.cs (app.Map("/api", api => { /*configs and route*/ });)

and modified .vs\config\applicationhost.config file like below to use virtual directory

<site name="ThreeCON.Web" id="2">
    <application path="/" applicationPool="Clr4IntegratedAppPool">
      <virtualDirectory path="/" physicalPath="C:\proj\src\app.web\wwwroot" />
      <virtualDirectory path="/api" physicalPath="C:\proj\src\app.api\wwwroot" />
    </application>
    <bindings>
      <binding protocol="http" bindingInformation="*:29999:localhost" />
    </bindings>
</site>

when i try to access the url localhost:29999/api while debugging, i'm getting 404 not found error (where localhost:29999/ is working fine)

But when i deploy the same to dev server by creating virtual directory in IIS, its working fine. so how can i fix this to work with IIS Express