Acyl Transfer Strategies as Transient Activations for Enantioselective Synthesis
Résumé
In order to circumvent reactivity or selectivity issues associated
with the addition of enolates to electrophiles, chemists have devised
innovative methods involving transient activating groups. One of
these powerful methods consists of the use of activated ketones, such
as -nitroketones, -dicarbonyl compounds or -ketosulfones, with
electrophiles possessing a latent hydroxy or amine function. In the presence
of a suitable catalyst, an enantioselective addition to the electrophile
is facilitated triggering a subsequent Claisen-type fragmentation
resulting in an acyl transfer. This subsequent step unveils the desired
mono-activated function while directly transferring the ketone, forming
in situ on the other side an ester or an amide.