I know I've read some Parenti that gets into it a bit, I'll take a look. Most were not literally executed, but the Soviets denied scientists acknowledgement for work, often they had as little knowledge of what they were really working on as possible (which may have hindered their contributions). But the only allegations attributing specific individuals their contributions that I've found before the collapse of the USSR appear in Western language sources, usually of those who were seemingly useful long enough or non-ideological enough to be sent home, and of those really just those that made their way to West Germany (and often ultimately the US) or were close to those that did.