497968-26-0Relevant articles and documents
Several convenient methods for the synthesis of 2-amido substituted furans
Padwa, Albert,Crawford, Kenneth R.,Rashatasakhon, Paitoon,Rose, Mickea
, p. 2609 - 2617 (2003)
Several new methods for the synthesis of differently substituted 2-amidofurans are described. The thermolysis of furan-2-carbonyl azide results in a Curtius rearrangement and the resulting furanyl isocyanate was trapped with various organometallic reagents. A second method consists of a C-N cross-coupling reaction of a bromo-substituted furan with various amides, carbamates, and lactams. The CuI-catalyzed cross-coupling reaction between furanyl bromides and amides furnished 2- and 3-substituted amidofurans in 45-95% yield. The third protocol used involves the reaction of cyclic carbinol amides with triflic anhydride. The reaction proceeds under very mild conditions to provide α-(trifluoromethyl)sulfonamido-substituted furans in high yield. The resulting iminium ion derived from the reaction of the hydroxy pyrrolidinone with Tf2O undergoes a facile ring opening as a consequence of the adjacent hydroxyl group to produce an imino triflate intermediate. Subsequent cyclization of this highly electrophilic imine with the oxygen atom of the adjacent carbonyl group leads to an imino dihydrofuran that reacts further with another equivalent of Tf2O to give the observed product.
Triethylborane induced radical reaction of gallium enolates with α-halo esters
Usugi, Shin-ichi,Yorimitsu, Hideki,Shinokubo, Hiroshi,Oshima, Koichiro
, p. 2049 - 2052 (2007/10/03)
Treatment of silyl enolates with methyllithium followed by an addition of gallium trichloride afforded the corresponding gallium enolates. The reaction of the resulting gallium enolates with α-halo carbonyl compounds in the presence of triethylborane as a radical initiator provided 1,4-dicarbonyl compounds in good yields.
