Centre for Sustainable Chemical Processes, Department of Chemistry, Durham Univertsity, Science Laboratories, South Road, Durham, DH1 3LE, UK.
Org Lett. 2011 Jul 1;13(13):3442-5. doi: 10.1021/ol201188d. Epub 2011 Jun 6.
CuCl(2), in the presence of a 2-ethyl-2-oxazoline ligand, is an effective catalyst for the room temperature, aerobic oxidation of hydroxamic acids and hydrazides, to acyl-nitroso and azo dienophiles respectively, which are efficiently trapped in situ via both inter- and intramolecular hetero-Diels-Alder reactions with dienes. Both inter- and intramolecular variants of the Diels-Alder reaction are suitable under the reaction conditions using a variety of solvents. Under the same conditions, an acyl hydrazide was also oxidized to give an acyl-azo dienophile which was trapped intramolecularly by a diene.
在 2-乙基-2-恶唑啉配体存在下，CuCl2 是一种有效的室温有氧氧化羟肟酸和酰肼的催化剂，分别生成酰基-亚硝基和偶氮二烯亲电试剂，这些亲电试剂通过与二烯的分子内和分子间杂[4+2]环加成反应被有效地原位捕获。在使用各种溶剂的反应条件下，[4+2]环加成反应的分子内和分子间变体都适用。在相同条件下，酰基酰肼也被氧化生成酰基偶氮二烯亲电试剂，该亲电试剂被二烯分子内捕获。
