Electron deficient enantioselective reduction

Vinyl phosphine oxides and phosphonates are highly electron-deficient and can undergo conjugate reduction much like their carbonyl counter parts. The group of Andersson has reported an enantioselective reduction of both to yield chiral phosphine oxides and phosphonates (Table 6) [67]. 

Starting from (E)-27 thus prepared, one route to access epoxy alcohols (E)-24 is the diastereoselective reduction of the chiral epoxy ketones (E)-25 after enantioselective epoxidation of (E)-27 (Route A). The alternative method requires the opposite combination of the two procedures, namely, enantioselective reduction of (E)-27 to (E)-26, followed by diastereoselective epoxidation (Route B). in the case of Route A, because attachment of the carbonyl group in (E)-27 renders the C—C double-bond electron deficient, nucleophilic as5nnmetric epoxidation should be the method of choice, and enantioselective versions are available for this purpose.On the other hand, electrophilic reagents are suitable for oxirane preparation in Route B. 

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