Lev Schnirelmann
Lev Genrikhovich Schnirelmann (born 1905 in Homel (Belarus), died 1938 in Moscow) was a Soviet mathematician who sought to prove Goldbach's conjecture. In 1931, using the Brun sieve, he proved that any natural number greater than 1 can be written as the sum of not more than 300,000 primes.
His other fundamental work is joint with Lazar Lyusternik. Together, they developed the Lyusternik-Schnirelmann theory, as it is called now, which is based on the previous work by Henri Poincaré, David Birkhoff, and Marston Morse. The theory has led to numerous advances in differential geometry and topology.
According to Pontryagin's memoir, Schnirelmann died in Moscow after committing a suicide.