Multivariate optimization of a cyclopropanation, the key step in the synthesis of 3,3,4,4-tetraethoxybut-1-yne

Article abstract of DOI:10.1021/op5001012

3,3,4,4-Tetraethoxybut-1-yne (TEB) is a versatile synthon that can be produced in a four-step synthesis. The third step of the synthesis is a cycloproanation, which has been thoroughly investigated and optimized by means of statistical experimental design and multivariate modeling. At the outset, an exhaustively pre-experimental design was performed resulting in a copious Ishikawa cause-effect diagram. In total six of the experimental variables were assessed to be of large importance and thus selected for further investigation by fractional factorial design. The results of that screening and first step optimization formed the basis for a response surface modeling (RSM) study. The RSM investigation was completed by using a central composite design from which a response surface was graphically produced as an iso-contour projection. The derived multivariate predictive model in terms the iso-contour projection plots were ultimately utilized to establish experimental conditions that concomitantly provided excellent yield (>99%) and minimized amounts of inputs and thus obtain the desired product at the lowest production cost and minimized side-streams.