Abstract
Excerpt: Efficiency is a central concept in modern organic synthesis. Cascade reactions, where multiple bond-forming events occur in one synthetic operation, not only encourage efficiency but also reduce waste by eliminating extra steps and often tedious purifications.1,2 In this communication, we report the efficient, regioselective one-pot synthesis of a variety of isoxazolidines from commercially available starting materials. Isoxazolidines are often used as intermediates in the synthesis of complex molecules,3,4 and are frequently present in biologically active compounds.5–7 They are valuable intermediates because the N–O bond can be easily cleaved under mild reducing conditions to afford 1,3-amino alcohols, which themselves are highly valuable synthetic building blocks.8 The most common method for the synthesis of isoxazolidines involves the 1,3-dipolar cycloaddition of a nitrone with an alkene to simultaneously generate an O–C and C–C bond, as well as up to three stereocenters (eqn (1)).9–15