An Enantioselective Synthesis of cis-4-tert-Butoxycarbamoyl-1-methoxycarbonyl-2-cyclopentene-A Useful, General Building Block

The amino acid derivative in the title represents an important building block for the synthesis of a number of biologically important targets such as the antiviral carbanucleosides and amidinomycin. By using asymmetric palladium‐catalyzed desymmetrization of meso‐2‐ene‐1,4‐diols, cis‐1,4‐dibenzoyloxy‐2‐cyclopentene can be converted to the enantiomerically pure title compound in only four steps. Chemoselective ester reduction allows entry into the domain of carbanucleosides, whereas double‐bond reduction provides the precursor for amidinomycin. In an ancillary study, a facile diastereoselective cis‐hydroxylation provides aminocyclopentitols, compounds that have proven to be potent glycosidase inhibitors. Biologically important targets, such as antiviral carbanuclcosides and amidinomycin, can be synthesized from the amino acid derivative shown below. This enantiomerically pure building block is available in only four steps from a symmetric diester. The key step in this sequence is an asymmetric palladium‐catalyzed desymmetrization.