Nicolaou, Tang and Wang. Chem. Comm., 2007, Advance Article. DOI: 10.1039/b704589a.
And again! This second publication (the third is due very soon…) by Nicolaou is another formal synthesis, actually going to the same intermediate that Snider did in the last post. Actually, looking at these two papers, alarm bells started ringing, as the retrosyntheses are not dissimilar:
Now I’m not trying to say that there was any foul-play here – just that this strategy seems quite popular! The interesting bit, I guess, is then the synthesis of that decalin, which thankfully uses an entirely different approach. The got to a quite complex intermediate very quickly by just doing a pair of enolate alkylations. With a few functional group transformations, they were then set for the most interesting reaction in this paper:
Now that’s a nice Stetter reaction! They state that they tried a number of carbene-based catalysts, but found that the triazole catalyst shown was optimal. I noticed that the catalyst has a per-fluoro phenyl group bolted-on – does this mean they could use Curran’s fluorous phase chromatography to separate it with ease? Anyway, it’s certainly a sweet method to put that system together.
I’ll blog the asymmetric synthesis shortly…