A Direct Synthesis of Highly Substituted π‐Rich Aromatic Heterocycles from Oxetanes

Abstract

The ubiquitous use of p-rich five-membered heterocycles has driven the development of new methods for their synthesis for more than acentury.Here,w edisclose ag eneral and reliable reaction manifold for the construction of highly substituted heterocycles through af acile Lewis-acid-catalyzed oxetane rearrangement. Notably,t his methodology employs ak eto-oxetanem otif as a1 ,4-dicarbonyl surrogate,w hichc an be synthesized using robust alkylation or alkenylation reactions,a nd thus obviates the need to access 1,4-dicarbonyl compounds via umpoled starting materials.W eh arnessed this reactivity to generate ab road range of substituted furans and pyrroles,a nd extended this methodology to produce benzofused versions thereof.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Enantioselective Desymmetrization of 3-Substituted Oxetanes: An Efficient Access to Chiral 3,4-Dihydro-2H-1,4-benzoxazines

“…Nevertheless, a transition metal free strategy for the catalytic enantioselective synthesis of an aforementioned motif is still highly desirable. In recent years, catalytic enantioselective desymmetrization of prochiral compounds has emerged as a powerful, albeit highly challenging, strategy for preparing a wide range of products with high atom economy. − Yet, in contrast to ring-opening and functionalizations, − asymmetric transformations of oxetanes into various heterocycles through catalytic enantioselective desymmetrization remains quite less explored. − In 2009, Jacobsen group reported the first intramolecular enantioselective desymmetrization of oxetanes catalyzed by Co­(III)-(salen) complexes, forming functionalized tetrahydrofurans in high enantioselectivities. More recently, the Sun group reported a series of intramolecular enantioselective desymmetrization − of oxetanes elegantly catalyzed with chiral phosphoric acids (CPA).…”