Upon exposure to singlet oxygen and dimethylsulfide, the addition products between 3-furaldehydes and Grignard reagents undergo an oxidative rearrangement to give 2-substituted 3-furaldehydes, in yields ranging from 26-83%. N-Aryl- and N-tosylpyrroles were similarly obtained if the corresponding nitrogen-containing precursors were used instead, in equally attractive yields (64-92%).
Addition/Oxidative Rearrangement of 3-Furfurals and 3-Furyl Imines: New Approaches to Substituted Furans and Pyrroles
作者:Ann Rowley Kelly、Michael H. Kerrigan、Patrick J. Walsh
DOI:10.1021/ja710988q
日期:2008.3.1
oxidative rearrangement proceeds through an unsaturated 1,4-dialdehyde intermediate. The alcohol then cyclizes onto an aldehyde, resulting in the elimination of water and rearomatization. On the basis of this proposed mechanism, we found that 3-furyl imines undergo the addition of organometallic reagents to provide furyl sulfonamides. Under the oxidative rearrangement conditions, 2-substituted 3-formyl
Oxidation of 3-Furfurylcarbinols with Bromine in Acetone-Water
作者:Piin-Jye Harn、Chu-Chung Lin、Hsien-Jen Wu
DOI:10.1002/jccs.200800035
日期:2008.2
Oxidation of 3-furfurylcarbinols 3a-e and 7 with bromine in acetone-water solution gave the 2-substituted-3-furfurals 4a-e and 8 in good yields, respectively. Reaction of 2-alkyl-3-furfurylcarbinols 9a and 9b with bromine in acetone-water gave the bromoalkyl 3-furfuryl ketones 10a and 10b as the major products. A reaction mechanism via the cis-trans isomerization of the 2-ene-1,4-diones 13 and 14 was