Application of the anionic homologous Fries‐rearrangement to the synthesis of 3‐alkylbenzofuran‐2(3H)‐ones

We have developed an effective organometallic‐based procedure allowing the employment of 2‐methylphenols as easily available starting materials in the synthesis of 3‐alkylbenzofuran‐2(3H)‐ones. The first step of this protocol, an anionic homologous Fries‐rearrangement, afforded 2‐(2‐ tert ‐butyldimethylsilyloxyaryl)acetamides, which were selectively metalated and monoalkylated at the benzylic position. Acidic work‐up of crude products afforded the desired heterocycles in satisfactory overall yields. Copyright © 2008 John Wiley & Sons, Ltd.     

Investigation of the regioselectivity of alkylation of 3-nitropyridin-2(1H)-ones

Alkylation of 3-nitropyridin-2(1H)-ones in the presence of bases affords N-alkylated products and sometimes O-alkylated products. The yields and relative amounts of N- and O-alkylated products depend substantially on the size of the substituent at the C(6) atom of pyridone.     

Sodium dithionite in the regioselective reduction of the ortho-positioned nitro group in 1-R-2,4-dinitrobenzenes

1-R-2,4-Dinitrobenzenes are regioselectively reduced with sodium dithionite at near-neutral pH into the product having amino group ortho to the substituent R. Although the yields of products varied from moderate to good, the procedure does not involve the use of transition metals.     

Redox‐Triggered CC Coupling of Diols and Alkynes: Synthesis of β,γ‐Unsaturated α‐Hydroxyketones and Furans by Ruthenium‐Catalyzed Hydrohydroxyalkylation

Direct ruthenium‐catalyzed C? C coupling of alkynes and vicinal diols to form β,γ‐unsaturated ketones occurs with complete levels of regioselectivity and good to complete control over the alkene geometry. Exposure of the reaction products to substoichiometric quantities of p‐toluenesulfonic acid induces cyclodehydration to form tetrasubstituted furans. These alkyne‐diol hydrohydroxyalkylations contribute to a growing body of merged redox‐construction events that bypass the use of premetalated reagents and, hence, stoichiometric quantities of metallic by‐products.     

Non-selectivity in the reaction of levoglucosenone with the sulfinyl allyl carbanion

Condensation of levoglucosenone with the carbanion ofrac-allyl phenyl sulfoxide, in contrast with reactions of this anion with the majority of other unsaturated ketones, proceeds without regio- or enantioselectivity to give a (1.0–1.8): 1 mixture of products of both 1,2- and 1,4-γ-addition of the allylic residue. Each product is a (1.2–1.6): 1 mixture of epimers at the asymmetric sulfur atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 157–159, January, 1999.