Council#13
The Omega Male
In the inner recesses of the Chancellor's private office, the Jedi confronted the Chancellor. Palpatine produced a lightsaber hidden in his sleeve and let the dark side of the Force flow through him. It granted him inhuman dexterity and speed, agility enough to quickly kill three Jedi Masters and force the mighty Mace Windu back. The two dueled, transforming the office of politics into an arena of lightsaber combat. Windu overpowered Palpatine the instant Anakin Skywalker came running into the offices. From Palpatine's thing on the Official Star Wars website
The Jedi barged into Palpatine's most private offices. Mace attempted to arrest the Chancellor, but Palpatine sprang into action. Brandishing a lightsaber, Palpatine dropped the guise of harmless politician and emerged as deadly Sith Lord. Sidious quickly killed Tiin, Kolar and Fisto and forced Windu back into the main office chamber. Just then, Anakin Skywalker arrived, disobeying Windu's direct order. That on Mace's
Anakin reported the Chancellor to Mace Windu, earning the Jedi Master's trust. Windu brought a team of capable Jedi warriors to arrest the Chancellor, but he refused to let Anakin come along. Left alone to stew in his tempestuous thoughts, Anakin realized that Palpatine could be his only chance at saving Padmé. He rushed to the Chancellor's office, to discover that Mace Windu was about to kill the Sith Lord. That on Anakin
None of them say that he knew Anakin was coming. It's possible that he might have, but so far we have nothing substantial to base it on