Enantiocontrol with a Hydrogen-bond Directing Pyrrolidinylsilanol Catalyst

A new bifunctional catalyst containing a silanol group
has been
designed and synthesized with high enantioselectivity in three steps.
The hydrogen-bonding properties of this pyrrolidinylsilanol have been
investigated using NMR binding studies and electrospray ionization
mass spectrometry (ESI-MS) analysis. The ability of the silanol group
to activate an electrophile and afford enantiocontrol through hydrogen-bond
directing effects has been demonstrated using an enantioselective
aldol reaction with isatin and acetaldehyde, affording up to 88% ee.