The iron(0)-catalyzed cross coupling of certain allylic ethers to 2,3-disubstituted 1,3-butadienes results in either a formal [4 + 4] ene reaction across the diene or in the net 1,4-insertion of the diene unit into the C-H bond at the 2-position of the allylic ether. The course of the reaction is determined by the ligands attached to the iron(O) catalyst. The active catalyst can be generated in situ, and reactions proceed catalytic in iron(O) at or near ambient temperatures. These new coupling reactions generate synthetically useful functionality (stereodefined olefin and an allylic ether or a protected carbonyl) on either side of the newly formed carbon-carbon bond. The results of deuterium-labeling experiments suggest a catalytic cycle which involves initial oxidative coupling of the diene and allyl ether in the mechanism of these reactions.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry