Pass MySql query to Eloquent Laravel

I have a query that when passing to eloquent returns me a syntax error.

SELECT order_id FROM timelines
WHERE order_id NOT IN (SELECT order_id FROM timelines WHERE supplier_approved_id) AND supplier_id = 2
GROUP BY order_id

Eloquent:

Timeline::select('order_id')
    ->whereRaw('order_id NOT IN', [], '( SELECT order_id FROM timelines WHERE supplier_approved_id )')
    ->where('supplier_id', 2)
    ->groupBy('order_id')
    ->get();