Otera's catalyst
# 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.

