An environmentally friendly oxidative cleavage of tetrahydrofuran-2-methanols to the corresponding g-lactones using ac atalytic amount of 2-iodo-N-isopropylbenzamide hasb een developed. Ther eactiono fv arious tetrahydrofuran-2-methanols with the catalyst in the presence of Oxone (2 KHSO 5 ·KHSO 4 ·K 2 SO 4 )a saco-oxidant in DMF at room temperature successfully affords the corresponding lactones in good to high yields,a nd recovery of the catalyst is readily accomplished using areductive work-up.T his method is notable because it enables the transformation of tetrahydrofuran-2-methanols to g-lactones under mild conditions without the use of any toxicheavy metals.
Synthesis of 10b-fluorinated analogues of protubonine A and its 11a-epimer was accomplished using fluorocyclisation of tryptophan-containing dipeptides with N-fluoro-2,4,6-trimethylpyridinium triflate to 3a-fluoropyrrolo[2,3-b]indoles as a key step. Acetylation of the indole nitrogen and the following diketopiperazine formation gave the 10b-fluorinated analogues of protubonine A and its 11a-epimer.
[4-Iodo-3-(isopropylcarbamoyl)phenoxy]acetic acid was developed as a highly reactive and easily separable catalyst for the oxidative cleavage of tetrahydrofuran-2-methanols to γ-lactones in the presence of Oxone® (2KHSO5·KHSO4·K2SO4) as the co-oxidant. The reactivity of this new catalyst was considerably greater than that of our previously reported catalyst, 2-iodo-N-isopropylbenzamide. The new catalyst and product were easily separated by only liquid–liquid separation without chromatography. In addition, using a mixture of nitromethane and N,N-dimethylformamide as the solvent and heating enabled a low catalyst loading, a short reaction time, and high product yield. Oxidative cleavage using the new catalyst can be used as a practical and efficient method for synthesizing γ-lactones.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.