I'll have to disagree, everywhere I look it seems that authoritarian regimes foster corruption way more than democracies. They tend to weaken institutions, specially those that would provide checks against corruption, in order to consolidate power. Developing a functioning burocracy free of corruption from scratch is very difficult under a democracy, but it is even harder under an authoritarian regime.
IF they are weakening institutions, then those institutions were already developed, hence it does not apply. The advent of authoritarianism does corrupt a functioning state. But statebuilding with democracy has been tried countless times, especially in ex-colonial countries and i don't know many cases where it worked.
