Old habits and common sense: a case of desulfurization

In our group meetings I always lament on how reluctant we are to change our set ways of running a given synthetic operation. I understand the argument of sticking to what works, but I just don’t get it when we are reluctant to give a chance to superior methodology, especially when it represents a synthetic operation that might be superior to our favorite tool. For instance, in our peptide work, we often run reductions of C-SH bonds into C-H bonds. What do we use in order to effect this transformation? We typically use Raney nickel… My main “beef” with this substance is its poor safety profile. The misery this reagent can bring when mishandled is considerable. Given the emphasis on safe laboratory operations these days, pyrophorics should be the first chemicals to be careful about. Yet, we continue to rely on that Raney nickel concoction. In this regard, Danishefsky’s radical desulfurization mediated by trialkylphosphites provides a marvelous and significantly safer alternative. Below is its mechanism and a paper that appeared some time ago.



In my view, one of the goals of modern chemistry research should be to replace hazardous reagents with alternatives that accomplish the same objective while minimizing risks. While technical expertise is a reliable antidote against mistakes in the lab, complacency and routine are among the dangers affecting everyone. And routine is the worst of them, a real bane of laboratory practice. Even experienced chemists may fall into this trap… A given reaction would go safely and without a glitch 100 times, but might abruptly fail without an apparent reason on the 101st attempt.

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