You might get somewhere with some languages, but I doubt you'll have great success with this in English, for example.
One reason is that English has many words for which there is no single pronunciation, but a variety of different pronunciations depending on the enviroment of the word. So, for example, in British English, the word are could be any of these:
Which one you get depends on whether the word is stressed or not, or stranded or not, plus whether it is followed by a vowel or not.
Secondly, there is the problem of silent letters. How could we meaningfully map the E at the end of are? How about CH in yacht or T in listen?
Another complication you have is discontinuous spelling rules. So, for example take the word:
- tome /toʊm/ (American English)
Here you cannot really just map the O onto the /oʊ/. It is represented in the orthography by the O and the E occurring on either side of a consonant.
However, you might be able to get quite a long way. It also depends what exactly the mapping is for, and what you mean by mapping phonemes onto letters. For example suppose you have the noun minute, in what sense does the U map onto /ɪ/? (And again what are you doing with the E there?) In some sense maybe, but it's not clear - or maybe it's just not clear to me.