Methylboronic acid dervatization followed by BSTFA

[rj_panet]

Hi,
I'm experimenting with a method that first uses methylboronic acid to derivatize sugars, then followed by BSTFA to add TMS to any free hydroxyl groups. However, the second step doesn't call for Trimethylchlorosilane.
My question is, does the excess, unreacted methylboronic acid act as a catalyst for the silylation?
And if anyone's wondering, I'm using the method described in Gross and Glaser (2004) RCMS vol 18 pp 2753-2764 and it's worked exactly as it should be on standard mixtures.
Cheers

[Fabiano]

BSTFA is one of the strongest TMS donors, usually you don´t need a catalyst as TMSCl or Pyridine.

I never worked with Methylboronic acid, but I guess it works as some way to avoid anomers and multiple pekas during analysis as hydroxylamine and boronhydride ( oxime and alditol methods). the excess should react with BSTFA.