Synthesis of Baylis-Hillman adducts
The samarium diiodide promoted addition of α-halo-α,β-unsaturated esters to carbonyl compounds led to (Z)-2-(1-hydroxyalkyl)-2,3-alkenoates in good yields and very high stereoselectivity. A mechanism is proposed to explain this transformation.
J. M. Concellon, M. Huerta, J. Org. Chem., 2005, 70, 4714-4719.
Silica gel-DABCO catalyzed oxidation of alcohols to aldehydes with chloramine-T followed by their Morita-Baylis-Hillman reaction with acrylonitrile or methyl acrylate gives good overall yields of the corresponding Morita-Baylis-Hillman adducts. The present work opens up a new and efficient synthetic route to Morita-Baylis-Hillman adducts directly from alcohols in a one-pot operation.
L. D. S. Yadav, V. P. Srivasta, R. Patel, Synlett, 2010, 1047-1050.
Various ketones as the electrophiles react in a one pot three-component coupling with an aluminum allenoate intermediate derived from ethyl propiolate and alluminium iodide to yield β-iodo Morita-Baylis-Hillman adducts with high yield and excellent Z-stereoselectivity.
S. Il Lee, G.-S. Hwang, D. H. Ryu, Synlett, 2007, 59-62.
A nickel(0)-catalyzed coupling of α-olefins and isocyanates in the presence of an N-heterocyclic carbene ligand proceeds preferentially at the 2-position of the olefin to provide α,β-unsaturated amides. N-tert-butyl amide products can be converted to the corresponding primary amides under acidic conditions.
K. D. Schleicher, T. F. Jamison, Org. Lett., 2007, 9, 875-878.
A P-cyclohexyl substituted ferrocenophane catalyst affords high levels of asymmetric induction in the organocatalytic [3 + 2] annulation reaction between allenes and electron-poor olefins.
A. Voituriez, A. Panossian, N. Fleury-Brégeot, P. Retailleau, A. Marinetti, J. Am. Chem. Soc., 2008, 130, 14030-14031.
A nucleophile-catalyzed asymmetric [3+2] cycloaddition of allenes with enones is described. The method has also been applied to reactions of trisubstituted olefins, thereby generating quartenary and tertiary stereocenters.
J. E. Wilson, G. C. Fu, Angew. Chem. Int. Ed., 2006, 45, 1426-1429.