Nikolai Brodskii,from the Siberian city of Irkutsk, was among the 239 passengers on the flight that disappeared over the sea between Malaysia and Vietnam on Saturday.
Rabbi Aharon Wagner from Irkutsk is believed to have contacted Mr Brodskii’s family after learning that he was on the plane.
Mr Brodskii, 43, was returning to Russia on Malaysia Airlines Flight MH370 after travelling to Bali, Indonesia, for a diving vacation.
The flight vanished without issuing a distress signal.
It is believed the plane had changed course and turned back towards Kuala Lumpur, from where it had taken off.
It emerged that two passengers had boarded the plane using stolen passports.
The Financial Times reported that the tickets for those two passengers had been bought by an Iranian middleman.
Mr Brodskii leaves behind a wife and two sons, aged 17 and 11.