Highly α-Selective Hydrolysis of α,β-Epoxyalcohols using Tetrabutylammonium Fluoride

Abstract

We report a simple method for the highly regio- and stereoselective hydrolysis of α,β-epoxyalcohols. Treatment of enantiopure epoxyalcohols derived from Sharpless epoxidation with TBAF/H2O resulted in exclusive ring opening at the normally disfavored α-position, providing access to arabino- or lyxo-configured triols with full preservation of stereochemical purity. The method was applied in syntheses of 5-deoxy-L-arabinose (26) and a family of bicyclic acetals based on the insect pheromone hydroxybrevicomin (4).

Catalytic Asymmetric anti‐Selective Nitroaldol Reaction En Route to Zanamivir

“…The use of (−)‐DET, however, resulted in the preferential formation of undesired β epoxide. Regioselective ring‐opening of the epoxide proceeded with aqueous TBAF to afford the triol with the desired stereochemical orientation (87 %),26 and the triol was then protected with Bn groups by using a conventional method to give 16 (91 % diastereomeric ratio 3.4:1). At this stage, the diastereomers could be chromatographically separated.…”

Stereoselective Synthesis of 1,2,3‐Triol Derivatives from α,β‐Unsaturated Acylsilanes

“…Thus, we considered that a similar nucleophilic addition reaction to 2,3‐dihydroxyacylsilane derived from the dihydroxylation of the alkene moiety of α,β‐unsaturated acylsilane and the following protodesilylation give the corresponding 1,2,3‐triol with high stereoselectivity (Scheme ). Such 1,2,3‐triol units having contiguous stereogenic centers are a very common pattern in the structure of many naturally occurring compounds; however, the facile stereoselective synthesis of desired isomers among four generable diastereomeric 1,2,3‐triols was less well known . So, our method will be useful for the stereoselective construction of 1,2,3‐triol derivatives.…”

Catalytic Asymmetric anti‐Selective Nitroaldol Reaction En Route to Zanamivir

“…[25] The use of (À)-DET, however, resulted in the preferential formation of undesired b epoxide. Regioselective ring-opening of the epoxide proceeded with aqueous TBAF to afford the triol with the desired stereochemical orientation (87 %), [26] and the triol was then protected with Bn groups by using a conventional method to give 16 (91 % diastereomeric ratio 3.4:1). At this stage, the diastereomers could be chromatographically separated.…”