Selective Reduction of Carbonyl Compounds with B-Cyclohexoxydiisopinocampheylborane

摘要

Since Brown and coworkers developed a new asymmetric reducing agent,diisopinocampheylchloroborane (IpcoBCl),for prochiral ketones in 1985,we have investigated extensively the general reducing characteristics of diisopinocampheyl-haloboranes such as IpC2BCl,IpcoBBr and IpC2BI toward organic functional groups.Subsequently,we found that all the reagents possess a very fascinating selectivity in the reduction of carbonyl compounds.Soon after,we also developed other derivatives such as Al-hydroxy- and Al-alkoxydiisopinocampheylborane and found that these reagents are one of the mildest reducing agents showing an excellent selectivity in the reduction carbonyl compounds.In our continuous effort to develop a new derivative,we prepared B-cyclohexoxydiisopinocampheylborane (Ipc_2BOChex),an alicycloalkoxy derivative,examined its reactivity toward general organic functional groups,and finally investigated its selectivity in the reduction of carbonyl compounds,in the hope of better understanding the nature of the reagent and exploring its role in organic synthesis.