I want to talk about unusual enolates today. The one implicated in Haufe’s anti-selective aldol reaction that was captured in his recent Org. Lett. publication is as good as it gets. There are many people who are interested in the SF₅ group these days. There are myriad reasons for this surge and I mentioned some of them in the past, particularly the materials science angle. Haufe’s work suggests that ester enolates that contain an SF₅ substituent are subject to some fairly reliable aldol chemistry, which is interesting because this represents a nice way to “plug” SF₅ into a chiral, sp³-rich environment. Up until now I have mainly seen the “aromatic” aspects of SF₅.

The starting ester used by Haufe is prepared on scale using a really cool reaction between SF₅Cl and a ketene. This process has been known since the 70’s, so check it out (reference 16 in Haufe’s Org. Lett.). I should mention that Professor Haufe of the University of Müenster is no stranger to fascinating transformations of organofluorine compounds. He has been at it for a number of years and is currently one of the Regional Editors of the Journal of Fluorine Chemistry.

http://pubs.acs.org/doi/full/10.1021/acs.orglett.6b00136