How to get the max ID in a Join Query in Laravel 5

My query is like this

$deals=DB::table('leadsheet')
            ->join('Deal', 'leadsheet.leadcode', '=', 'Deal.leadcode')
             ->join('benefits', 'leadsheet.leadcode', '=', 'benefits.leadcode')
             ->join('delegatedealinfo', 'leadsheet.leadcode', '=', 'delegatedealinfo.leadcode')
              ->join('vipbooking', 'leadsheet.leadcode', '=', 'vipbooking.leadcode')
             ->where('id', DB::raw("(select max(`id`) from vipbooking)"))
           ->where('leadsheet.leadcat', '=','Delegates')

            ->get();

So I have following table

1.leadsheet 
   -- leadcode
   -- leadcat
2.Deal
   -- leadcode
3.benefits
   -- leadcode
4.delegatedealinfo
   -- leadcode
5.vipbooking
   -- leadcode

what I am trying to do is

get all the maximum id of vipbooking form where leadcode is same as all the leadcode from leadsheet where leadsheet.leadcat= Delegates

My only problem is MAX ID for vipbooking form is not working

Can any one one help me out

Thanks

via Chebli Mohamed