Synthesis of Pharmaceutical Intermediates Aiming at Construction of Optically Active Tertiary Alcohols as a Key Technology

In recent years, there has been a large number of what are called standard preparations, such as asymmetric hydrogenation using asymmetric reduction catalysts typified by BINAP and methods using enzymatic hydrolysis, that are reliable from an industrial point of view for the synthesis of optically active secondary alcohols. Furthermore, there are many producers of pharmaceutical intermediates that cite optically active secondary alcohols as an area of strength. On the other hand, there is a focus on the synthesis of optically active tertiary alcohols as a field where there are few standard industrial preparations and for which organic synthesis is extremely challenging from an academic point of view. Since optically active tertiary alcohols cannot be synthesized by asymmetric hydrogenation when asymmetric synthesis is presumed, asymmetric carbon-carbon bonds must be constructed. However, ketones, which are sterically difficult to recognize must be used as the electrophilic agent for their construction instead of aldehydes, which are easily recognized. However, even though the construction of asymmetric carbon-carbon bonds with aldehydes is an important academic field in current organic chemistry and many researchers are studying it day in and day out, there are not many industrially reliable preparation methods at present, and there are even fewer asymmetric reactions that can be used industrially. Under these circumstances, we assumed that as challenging as this field is, it was a technical area that should be targeted in the field of pharmaceutical intermediates, which will become increasingly competitive in the future. So we decided to carry out the development of a method for synthesizing pharmaceutical intermediates for which the key is the construction of optically active tertiary alcohols. In this paper, we will introduce the development of a method for synthesizing intermediates for medicines for treating frequent urination as an example of this.