title: Otera's catalyst
text: # Otera's catalyst
  
  Otera's catalyst, named after Japanese chemist Junzo Otera, is an organostannane compound which has been used as a transesterification catalyst. This isothioscyanate compound is a member of a family of organostannanes reported by Wada and coworkers, and elaborated upon by Otera and coworkers.
  
  ## Preparation
  
  This class of compounds may be prepared generally by the reaction of an organotin halide and oxide:
  
      2 $R_2SnO$ + 2 $R_2SnX_2$ → $(XR_2SnOSnR_2X)_2$
  
  In particular, the thiocyanate compound was prepared by the reaction of dibutyltin oxide with dibutyltin diisothiocyanate. Otherwise, this compound is not commercially available.
  
  ## Applications
  
  This thiocyanate compound can be used as a transesterification catalyst. Although it is not well known, it has been used in a number of total syntheses.
  
  In this application, the reaction occurs via the displacement of the bridging isothiocyanate ligands with the incoming alcohol to form an alcohol-bridged active catalyst. Tin acts as the Lewis acid, and gives the transesterified product.
  
  