Abstract
The key step in the syntheses of highly substituted trans-3,4-dihydroxypyrrolidines is introduction of bromide by stereospecific and regiospecific Hanessian-Hullar reactions; benzylidene lactones of L-rhamnonolactone and 6-deoxy-this should be small unnpercase D not L why can I not correct this-gulonolactone allow introduction of N at C2 with inversion or retention of configuration. Initially a protecting group, the benzylidene acetal then provides a bromide at C5 to allow formation of the pyrrolidine ring. With silyl protecting groups, bromide was introduced at C5 with inversion of configuration whereas benzoyl protection gave a mixture of retention and inversion, indicative of neighbouring group participation in a Hanessian-Hullar reaction. Four stereoisomeric pyrrolidines - iminosugar mimics of α- and β-L-rhamnulose and α- and β-6-deoxy-D-sorbose were prepared. Only the α-L-rhamnulose mimic showed moderate inhibition of rhamnosidase but some were good inhibitors of α-glucosidases; none inhibited rhamnose isomerase and they had a small effect as synthetic inducers of the rhamnose catabolic operon in E. coli.
Original language | English |
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Article number | 130758 |
Journal | Tetrahedron |
Volume | 76 |
Issue number | 1 |
Early online date | 6 Nov 2019 |
DOIs | |
Publication status | Published - 3 Jan 2020 |
Keywords
- Benzylidene acetals
- Deoxysugars
- Glucosidase inhibitors
- Hanessian Hullar reaction
- Iminosugars
- Pyrrolidine synthesis
- Rhamnosidase inhibitors
- Sugar mimics