E- and Z-Stereoselectivity in the preparation of enamides from glycidyl sulfonamides and carbamates

Brown, Jack A and Chudasama, Vijay and Giles, Melvyn E and Gill, Duncan M and Keegan, Philip S and Kerr, William J and Munday, Rachel H and Griffin, Karen and Watts, Andrew (2012) E- and Z-Stereoselectivity in the preparation of enamides from glycidyl sulfonamides and carbamates. Organic and Biomolecular Chemistry, 10 (3). pp. 509-511. ISSN 1477-0520 (https://doi.org/10.1039/c1ob06569f)

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Abstract

Treatment of glycidyl sulfonamides with LDA delivers the corresponding enesulfonamide with good selectivity for the E-isomer, whereas the corresponding carbamates exhibit selectivity for the Z-enecarbamate. An E1cB elimination mechanism proceeding from a substrate–base chelate complex is advanced as rationalisation of the latter set of Z-selective outcomes.