My lab has been interested in challenging hemiaminals to do things they are typically not known for. Below is an example from Kim’s lab, showing how one can be really resourceful with hemiaminals. I have always been a fan of this sort of chemistry and, earlier today, rediscovered this cool sequence while going through my “paper vault”. Access to either of the two amino alcohol diastereomers is at stake in this chemistry. The syn diastereomer is accessible directly from the hemiaminal by way of conjugate addition. What about the anti version? In order to get that, you oxidize the hemiaminal into the corresponding hydroperoxy species, which transfers its oxygen atom to the nearby olefin under basic conditions the way any hydroperoxide would do. While this chemistry is now several years old, it does attest to how useful hemiaminals can be.