Bosporus is 30 km long, 700 m at the narrowest and under 4 km for the whole 30 km. Try to sail up Bosporus with broadsides to Napoleon´s guns along the tops of the bluff? Tricky in 1453, and hard with the shore guns of 1799. And with several km of Bosporus that is too hot for Royal Navy to enter, small boats and ferries can shuttle over that section of Bosporus.The Middle East won't be conquered. Nappy does not have the Navy to cross the Bosporus while the Royal Navy can block him. It is the Balkans, and Balkans alone.
If Napoleon takes Acre, would he turn east to India? Or west to go home through Anatolia, Constantinople and Vienna?