In recent years, allenamides have emerged as a useful functional group in organic synthesis. In our own work, we encountered the need for accessing γ-substituted chiral allenamides that could be used for new synthetic methodologies. Here, we report a new way to access 2,5-disubstituted dihydrofurans, which serve as a template for RNA ribose sugars.
Utilizing Seebach's protocol, the TMS protected N-propargyl imidazolidinone was converted to the corresponding allenyl alcohol in high diastereomeric ratios. Cyclization using PPTS or TBAF afforded the 2,5-disubstituted dihydrofurans, which can be functionalized further using hydrogenation, dihydroxylation, and lewis acid mediated removal of the auxillary.
New Reactions and Methodology, Materials, Total Synthesis, Process R&D
8:00 PM-10:00 PM, Sunday, 28 August 2005 Washington DC Convention Center -- Hall A, Poster