A deconjugative alkylation/Diels-Alder cycloaddition strategy to synthesize 2-substituted bicyclic scaffolds

作者：Zhang Wei; Ghiviriga Ion; Grenning Alexander J^*

来源：Tetrahedron, 2017, 73(29): 4076-4083.

DOI：10.1016/j.tet.2016.11.055

• Knoevenagel adducts
• Deconjugation
• Diels-Alder cycloaddition
• Decalins and hydrindanes
• CeC cleavage

Knoevenagel adducts derived from alpha,beta-unsaturated aldehydes and a malonic acid derivative can undergo deconjugative alkylation using dienophile-functionalized alkyl iodides. The single step reaction is twofold significant: (a) The electron-deficient diene (alpha,beta-unsaturated aldehyde Knoevenagel adduct) is deconjugated from the esters, resulting in an electronically neutral diene and (b) tethers the diene and dienophile, which allow for intramolecular cycloaddition to bicyclic systems bearing a malonic acid derivative at the 2-position. The sequence thus converts simple reagents into natural product relevant bicyclic scaffolds. We also disclose an unexpected Diels-Alder cycloaddition/aromative C-C cleavage reaction that results due to the malonate's location at the 2-position. Published by Elsevier. Ltd.

• 出版日期2017-7-20