Mukaiyama Thioester SynthesisSeptember 25th, 2011
I have made it a rule not to participate in blog carnivals. There is something disturbing about them. Perhaps it’s the association of carnivals with fun, which I try to limit in my life. Instead of organizing and participating in “carnivals”, I do exactly the same thing and call them “roundtables”. It’s so much more professional and so much less fun.
But ever since neutrinos decided to disobey the speed limit, I’ve been reconsidering my adherence to all of the rules in my life—including my self-imposed prohibition of carnivals. The good people at C&EN are hosting a blog carnival this month in honor of the International Year of Chemistry, and I feel strangely compelled to participate. The subject: “Your favorite chemical reaction”.
Fortunately, I didn’t need to conduct my usual 200 hours of background research to write this post, because I actually wrote it in January 2007. My favorite reaction is the same now as it was then:
I came across the above reaction while thumbing through a random issue of Chemical Reviews whilst consuming a carton of curry chicken from Yenching Restaurant. It looks like the reaction can be traced to this paper by Mukaiyama from 1970. Much like Charlie Brown’s obsession with a bit of cartoon strumpet known to him only as the little red-haired girl, I find myself in the predictament of having fallen in love with a reaction that has no name. But a reaction so lovely should not have to go nameless for a minute longer. Henceforth, the reaction shall be known as the Mukaiyama Thioester Synthesis in all lands and kingdoms for perpetuity. Go forth and spread the gospel. Yields are risen.
Here is what I believe to be the (shorthand) mechanism for this dandy:
What do I find so compelling about this beauty of a reaction? Perhaps it’s the involvement of my favorite compounds, thioesters? Perhaps it is the generation of a notoriously strong phosphorus-oxygen bond to serve as the driving force for the reaction? Perhaps it is the neat nucleophilic attack of the phosphine on the disulfide in a process that must be similar to thiol-disulfide interchange? Perhaps it is the fact that this single reaction has all of these things wrapped into one? I don’t know.
And that’s all I have to say about that. Having looked over the other entries in the carnival, I find it unfortunate how far off-base the other contributors have been. There is nothing about any other reaction that could justify its being someone’s favorite above Mukaiyama Thioester Synthesis. The reaction is clearly the greatest in history.