What car built after 1945 does not have syncros?  Syncros do not affect shifting into first from neutral and will never be a problem if you keep the clutch depressed while in neutral.  It's only if you let the clutch out that can cause a problem shifting into neutral and simply letting the clutch out and then pushing it in will alleviate the  problem.  Large commercial trucks incorporate a clutch brake to stop the transmission gears from turning to allow putting the truck into gear.  This is why you should always sit at a traffic light with the car in gear and the clutch disengaged.