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The CuBr2-catalyzed enantioselective allenylation of terminal alkynols with carbon chains of different lengths has been developed. Compared with (S)-α,α-diphenylprolinol, the reaction using (S)-α,α-dimethylprolinol as the chiral amine afforded optically active 1,3-disubstuted allenols with higher ee-values. Both aliphatic and aromatic aldehydes could be applied. The naturally occurring phlomic acid was synthesized in four steps from commercially available hex-5-yn-1-ol. [ABSTRACT FROM AUTHOR]

A comprehensive study on aerobic oxidation of benzylic alcohols to carboxylic acids with a catalytic amount each of Fe(NO3)3·9H3O, TEMPO, and KCl is conducted. Various synthetically useful functional groups are well tolerated in the reaction. Distinct electronic and steric effects are observed in the reaction: electron-withdrawing groups accelerate the reaction while electron-donating groups make the reaction slower, and ortho-substituted substrates react slower than meta-substituted substrates. Several large-scale reactions (100 mmol) are conducted using a slow air flow of 30 mL/min to demonstrate the practicality of this method in an academic laboratory. [ABSTRACT FROM AUTHOR]

We have demonstrated two improved methods for the synthesis of carbohydrate-based terminal allenes from propargyl or homopropargyl glycosides. The reaction of propargyl or homopropargyl glycosides with paraformaldehyde (2.5 equiv) in the presence of copper(I) iodide (10 mol%) and diisopropylamine (1.8 equiv) or copper(I) iodide (50 mol%) and dicyclohexylamine (1.8 equiv) produces sugar-linked terminal allenes in 50-79% yield. [ABSTRACT FROM AUTHOR]

Under the catalysis of palladium acetate, 1,2-allenylpalladium formed from propargylic carbonates may react with two molecules of benzyne to afford phenanthrene derivatives by cyclization and β-H elimination [ABSTRACT FROM AUTHOR]

We have demonstrated a very general method for the preparation of essentially any terminal 2,3-allenol from the corresponding alkynols, which may be easily available from propargylic alcohols by alkylation, or from terminal alkynes by deprotonation and 1,2-addition with aldehydes or ketones, and subsequent base-catalyzed triple-bond migration. [ABSTRACT FROM AUTHOR]

A practical aerobic oxidation of propargylic alcohols using Fe(NO3)3.9H2O, TEMPO and sodium chloride in toluene at room temperature was applied to various type of propargylic alcohols affording α,β-unsaturated alkynals or alkynones in good to excellent yields. This protocol could be applied in academic laboratories as well as in industrial-scale production. [ABSTRACT FROM AUTHOR]

Different 2,3,5-trisubstituted furans have been regioselectively synthesized through a ring-opening cycloisomerization of functionalized cyclopropenyl carboxylates with moderate to excellent yields by using tri(2-furanyl)phosphine as the catalyst. [ABSTRACT FROM AUTHOR]

Propiolaldehyde was prepared by the oxidation of propargyl alcohol using molecular oxygen as the oxidant under atmospheric pressure and room temperature in a decent yield. Compared to the previous method with CrO3, such a protocol avoids the use of a stoichiometric amount of oxidant, and the workup procedure is much more eco-friendly and convenient affording a higher yield of the product. [ABSTRACT FROM AUTHOR]