The 2nd Siege of Coruscant

Prelude
By 243 ABY, under a year before the war began, the Mandalorians had pushed the Jedi off Mandalore, and began a large push into Alliance space, though casualties were still fairly large. In an attempt to avoid a Second Infinite War, the Mandalorians would sanction an attack on the lightly defended Coruscant, even though it was a major economic hub of the Alliance, it was far from the front lines, and surrounding systems, in theory, would be needed to be taken to pave the way for a large enough fleet to take Coruscant, and as such the surrounding systems were highly defended, while still having little to no ships in the region. After a group of spies sent by the Mandalorians would return, telling that the garrison at Coruscant had recently dropped in numbers due to men being brought to the front, they'd decide to send a fleet to swiftly take the planet.

First Days
The 7th Fleet would enter hyperspace by Coruscant, beginning an approach. The small Alliance fleet there, mostly small Corvettes, would attempt to delay them, but ultimately forced to retreat to the surface for repairs. The Mandalorians had brought a few ships that were outfitted to be able to jam transmissions from regions of the planet, stationing them all across Coruscant's orbit with small escorts, disabling the ground forces from calling for help without sending a blockade runner, which would be extremely dangerous, and most would be needed for defending Coruscant's atmosphere from fighters.

First Ground Incursions
The first ground incursions ended in Mandalorian successes, due to how spread out the Alliance forces were. Due to many Alliance sympathizers being within striking distance of the Mandalorians, and without assurance from the army, Militias would form, and ultimately be successful in defending alot of undefended regions of the planet. The Jedi would soon learn of the dire situation, and commit a large amount of Jedi to fight across the planet, and begin to lose many Jedi due to the raw skill of the Crusaders.

Attack on the Senate
The Old Senate Building, now being the home of a backup senate and many Coruscant Diplomats, Representatives and Ambassadors, came under attack when two Squadrons of Crusaders landed nearby and launched an attack on the Building. The Crusaders, believing the Senate would be lightly guarded, entered the building, but were easily beaten back by the Senate Guard, who were far more skilled than they were. Both Squadrons were almost destroyed before they got within range of the officials, and forced to retreat, securing the Senate Building's safety.

Last Days
The Mandalorians steadily lost ground as the combined efforts of the Alliance and sympathizers would be overwhelming. Grandmaster Natalia H'edan sanctioned for 20 Jedi to launch in two cloaked stealth cruisers respectively, and board two of the capital ships. The Jedi were successful in reaching their destination, and landed in their respective capital ships, making short work of the crew on the way to the Bridge. Upon reaching the bridge, the Jedi reach a grim realization that the planet's shields had just been lowered, and a Mandalorian ship was preparing to fire on the Jedi Temple and surrounding districts. In order to save the lives of thousands of Jedi, and preserve the Temple, the Ten Jedi aboard one of the cruisers would turn the ship to face the Mandalorian one, and activate the hyperdrive for co-ordinates on the other side of the Coruscant System. The Capital Ship rammed into the other at light speed, savagely ripping both apart and simultaneously destroying 2 Capital ships. However, the Jedi on the other ship sensed a trap, and attempted to escape, most being gunned down, leading to the largest loss of Jedi life in one confrontation during the battle. However, due to the loss of two capital ships, and the deterioating condition on the ground, they'd withdraw, leaving those who were still on the planet to fight to the death.

Aftermath
In the grand structure of the war, it was not a large loss, but it was used for extensive propaganda by the Alliance