It's an active area of research. There is, for example, the RNA world hypothesis, which you can easily research online if you're interested.
PS what Pasteur showed was that modern-day bacteria, yeasts, etc. do not form in sterile chicken broth, juice, etc. (the basis of canning), in a few months or years. His discovery says absolutely nothing about the chemical processes in the early atmosphere an hydrosphere, where the chemical conditions were quite different, and there was much more time.. (No-one is proposing that primoridial soup is chicken broth!)