The US announced sanctions this week but immediately suspended them to give more time for talks.
However, it suspended them for 180 days to allow further talks to take place in London and at a meeting of G20 nations in July.
Mr Sunak is expected to push for an agreement on taxes and call for all global businesses to commit to climate reporting.
Speaking ahead of the G7 meeting, Mr Sunak said: “Securing a global agreement on digital taxation has also been a key priority this year – we want companies to pay the right amount of tax in the right place, and I hope we can reach a fair deal with our partners.
“I’m determined we work together and unite to tackle the world’s most pressing economic challenges – and I’m hugely optimistic that we will deliver some concrete outcomes this weekend.”
Microsoft Round Island One is resident in Bermuda and the profit it generated last year is equal to nearly three-quarters of Ireland’s GDP.
All G7 countries, bar the UK, have supported a proposal from the US for a global minimum corporate tax rate of 15% that could raise $50-$80bn for governments around the world.
‘Deal within reach’
They wrote: “We are confident it will create the momentum needed to reach a global agreement at the G20 in Venice in July. It is within our reach. Let’s make sure it happens. We owe it to our citizens.”
The Biden administration initially pushed for a global minimum corporate tax rate of 21% but has now retreated to 15%. However, officials have said that’s regarded very much as a “floor”.
Finance ministers from the US, Japan, France, Canada, Germany and Italy will be attending the meeting at Lancaster House, along with representatives from the European Commission, the Eurogroup, the World Bank, the International Monetary Fund and the Organisation for Economic Co-operation and Development.