Ring Opening of Aziridines by Pendant Silanols Allows for Stereospecific Preparations of 1’-Amino-Tetrahydrofurans

We have developed a highly stereospecific cyclization of aziridine silanols into 1’-aminotetrahydrofurans. Our protocol of stirring substrate with 10 mol% of Sc(OTf)3 and 1 equivalent of NaHCO3 in CH2Cl2 is mild and compatible with a range of activating aziridine N-substituents and functional groups on the alkyl chains. In all cases examined, trans di-substituted aziridine silanols give products with an erythro configuration; conversely, cis di-substituted aziridine silanols give products with a threo configuration. While literature syntheses of 1’-amino-tetrahydrofurans exist, only one example, contemporaneous with our work, uses a similar cyclization for their construction. Control experiments demonstrate that, for this transformation, the silanol is not particularly privileged, and a variety of protecting groups on the alcohol are compatible with product formation.