Cambridge's Beth Shalom Synagogue has completed the purchase of new premises, but still needs to find £800,000 to finish the £1.7 million project.
With planning permission approved by the council, work is due to start before the end of the year on the Auckland Road site, using the £900,000 already raised.
A community room, library, bike racks and disabled parking will be among features of the development for the 250-strong congregation.
The project is supported by comedian Sacha Baron Cohen, a former Cambridge student, and actress Rachel Weisz, whose relatives are Beth Shalom members.