Molybdenum(0) and tungsten(0) catalysts with enhanced reactivity for allylic substitution: regioselectivity and solvent effects

Malkov, AV; Baxendale, IR; Mansfield, DJ; Kocovsky, P

Abstract

The binuclear Mo(II) and W(II) complexes 28a,b and 29a,b have been developed as pre-catalysts for allylic substitution with β-dicarbonyl nucleophiles. These complexes are reduced in situ to Mo(0) and W(0) catalytic species 30a,b and 31a,b by excess of NaH, employed to generate sodiomalonate nucleophiles, or by DIBAL-H. 1,3-Dioxolane and 1,4-dioxane, when used as solvents, substantially accelerate the reaction. These new catalysts exhibit “traditional” Mo regiochemistry, i.e., the nucleophilic attack occurring preferentially at the more substituted carbon (5 → 9; 37 → 38), unless an additional factor, such as further coordination to another moiety of the allylic electrophile takes part (41), as in the case of the geranyl-type substrates (32 or 33 → 36).

Citation

Malkov, A., Baxendale, I., Mansfield, D., & Kocovsky, P. (2001). Molybdenum(0) and tungsten(0) catalysts with enhanced reactivity for allylic substitution: regioselectivity and solvent effects. Journal of the Chemical Society. Perkin transactions 1, 1234-1240. https://doi.org/10.1039/b100903f

• Journal Article Type: Article
• Acceptance Date: Mar 19, 2001
• Online Publication Date: Apr 26, 2001
• Publication Date: 2001
• Deposit Date: Jul 14, 2014
• Journal: Journal of the Chemical Society, Perkin Transactions 1
• Print ISSN: 1472-7781
• Electronic ISSN: 1364-5463
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Issue: 10
• Pages: 1234-1240
• DOI: https://doi.org/10.1039/b100903f
• Public URL: https://durham-repository.worktribe.com/output/1425883