Regioselective Intramolecular Carbon-Hydrogen Insertion in Copper-Catalyzed Carbenoid Decompositions of cis-1-Methyl-3-Arylcyclohexane-1-Diazomethyl Ketones : Some Synthetic Applications

Recently, we have developed¹ a new route for the stereo-specific introduction of an angular carboxyl or functionalized methyl groups² in a rigid hydrophenanthrene moiety. The key step in this approach is a regioselective intramolecular α-keto carbenoid insertion across the benzylic C-H bond (at C-4a) in CuSO₄-catalyzed thermal decomposition of the diazoketones and to the corresponding tetracyclic ketones and in moderate to good yields. A modified procedure³ of carbenoid decomposition of these diazoketones, in the presence of Cu₂O under irradiation with tungsten filament lamp, improves the yields of the desired C-H insertion products. Thus, the ketones and have been prepared now in consistently higher yields (53-55%) from the pure diazoketones , m.p. 125-127°, and , m.p.     

Polyethylene Glycol–Enhanced Chemoselective Synthesis of Organic Carbamates from Amines,CO2, and Alkyl Halides

An efficient and environmentally benign method for the synthesis of organic carbamates was developed. Amines, CO₂, and alkyl halides underwent a three-component reaction with the aid of K₂CO₃ and polyethylene glycol (PEG, MW = 400), affording the organic carbamates under ambient conditions. PEG could presumably act as a solvent and phase-transfer catalyst (PTC). Notably, the presence of PEG could also depress the alkylation of both the amine and the carbamate, thus resulting in enhanced selectivity toward the target carbamate.

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Novel Synthetic Routes of 3-Methoxypropanal from Glycerol

A new synthesis of 3-methoxypropanal from glycerol was presented. With this new approach, the conversion of glycerol to 3-methoxypropanal can be effected in moderate yield using catalysts of copper sulfate and polyethylene glycol (PEG).

Synthesis of Bis(indolyl) Methanes in Catalyst- and Solvent-Free Reaction

Efficient synthesis of bis(indolyl) methanes by the reaction of indoles with various carbonyl compounds in the absence of catalyst and solvent afforded the corresponding bis(indolyl) methanes in excellent yields.     

An Improved Synthesis of 4-Cycloheptenone

A previous paper² described the chemistry of 1-aza-4-cyclo-octene 1 which we prepared from 4-cycloheptenone 2 according to the method of Bahurel et al.³ This procedure involves the condensation of cis-1,4-dichloro-2-butene with ethyl sodio-acetoacetate, yielding, a mixture of four isomers 3–6. The entire mixture is then heated with aqueous potassium hydroxide under reflux for four hours. Under these conditions 5 undergoes decarbethoxylation to yield 4-acetylcyclopentene 7, while 3 yields 2, presumatly by Cope rearrangement atid decarbethoxylation (2 is present in almost negligiblequantity but was reported³ to also yield 2).     

Efficient Synthesis of Bis(heterocyclyl)methanes

The reaction of pyrrole/furan aldehyde with Grignard reagent and pyrrole/N-methyl pyrrole in sequence allows efficient synthesis of a number of meso-elaborated bis(heterocyclyl)methanes, which are otherwise difficult to obtain through a direct aldehyde condensation route.      

Novel and Efficient Synthesis of tert-Butyl-2-(4-(2-aminoethyl)phenylthio)-2-methylpropanoate,a Key Intermediate in the Synthesis of Ureido Thioisobutyric Acid

A convenient and cost-effective synthesis of pharmacologically important tert-butyl-2-(4-2-aminoethyl)phenylthio)-2-methylpropanoate from commercially available 2-2-phenyl-1-ethanol is described.