= 1 The reactions have not been optimized with regard to the stoi-chiomctry of sodium borohydride. It seems evident that in most cases the large excess of sodium borohydridc is unnecessary. For example, reaction of I (10.8 mmol) with a slight excess of sodium borohydride (1 1.5 mmol)(method B2) gave an 80 '}~(, yield of 3, while reaction of 1 (10.8 mmol) with less than an equimolar amount of sodium borohydride (5.8 mmol)(method B2) ...