Cyclic Vinyl Ethers as the Products of Cyclisation of 2,5,5-Triethyl-2-alkynyl-3,4-bis(hydroxymethyl)pyrrolidine-1-oxyls
M. M. GULMAN1,2, S. A. DOBRYNIN1, YU. V. GATILOV1, I. A. KIRILYUK1
1Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
Keywords: nitroxide, alkynes, Favorsky reaction, Kucherov reaction, vinyl ethers
Abstract
2,5,5-Triethyl-2-alkynyl-3,4-bis(hydroxymethyl)pyrrolidine-1-oxyls (alkynyl = C≡CR, and R = H (2), C(Me)2OH (1), Ph (7)) undergo cyclisation on heating with sodium hydroxide to form cyclic vinyl ethers, the derivatives of 6-methylene-hexahydro-1 H -furo[3,4-b]pyrrole-1-oxyl. A bicyclic radical derived from radicals 1 or 2 is capable of reversible addition of alcohols to the vinyl group in the presence of acids. Cyclisation of radical 7 in the acid environment in the presence of mercury acetate follows a different route, with the formation of 2,2,7a-triethyl-3-(hydroxymethyl)-6-phenyl-1,2,3,3a,4,7a-hexahydropyrano[4,3-b]pyrrole-1-oxyl.
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