Trityl perchlorate-mediated

The trityl perchlorate mediated reaction of 1-0-acylsugars with alcohols is successfully carried out at 0 °C and the corresponding 0,-glycosides are stereoselectively produced (47). 

Initially, the titanium(IV) chloride-mediated aldol reaction of silyl enolates tvith aldehydes tvas investigated [20] and a catalytic amount of trityl salt 60 (e.g. trityl perchlorate) vas found to promote the aldol reaction (Eq. (27)) [35]. Whereas the original reaction is performed by using a stoichiometric amount of titanium(IV) chloride, 5-10 mol% trityl salt is sufficient to drive the aldol reaction to completion. One interesting finding in this catalytic reaction is that the silicon enolate reacts vith aldehydes to give the corresponding aldol adducts as their silyl ethers 61. 

---