:Oxo-Diels–Alder reaction

{{Short description|Chemical reaction}}

{{Reactionbox

| Name = Oxo-Diels–Alder reaction

| Type = Cycloaddition

| NamedAfter = Otto Diels
Kurt Alder

| Section3 = {{Reactionbox Identifiers

| RSC_ontology_id = 0000310

}}

}}

An oxo-Diels–Alder reaction (also called an oxa-Diels–Alder reaction) is an organic reaction and a variation of the Diels–Alder reaction in which a suitable diene reacts with an aldehyde to form a dihydropyran ring. This reaction is of some importance to synthetic organic chemistry.

:Oxo Diels–Alder reaction general

The oxo-DA reaction was first reported in 1949A Diels–Alder Type Reaction with Formaldehyde Thomas L. Gresham, Thomas R. Steadman J. Am. Chem. Soc., 1949, 71 (2), pp 737–738 {{doi|10.1021/ja01170a101}} using a 2-methylpenta-1,3-diene and formaldehyde as reactants.

:Oxo Diels–Alder reaction Gresham 1949

Asymmetric oxo-DA reactions (including catalytic reactions) are well known.Tetrahedron Report number 869 Asymmetric hetero-Diels–Alder reactions of carbonyl compounds Helene Pellissier Tetrahedron 65 (2009) 2839–2877 {{doi|10.1016/j.tet.2009.01.068}} Many strategies rely on coordinating a chiral Lewis acid to the carbonyl group.