Romualdo Caputo

Synthesis of Enantiopure N-and C-Protected homo-β-Amino Acids by Direct Homologation of α-Amino Acids ¶

Abstract Enantiopure N-and/or C-protected homo-β-amino acids are prepared readily and in good yields from N-protected α-amino acids with the same side chain, via reduction of the carboxyl function and conversion of the resulting N-protected β-amino alcohol into the corresponding β-amino iodide and then β-amino cyanide. The key step of this strategy is represented by the synthesis of the enantiopure N-protected β-amino iodides 2 and 3 that are smoothly obtained from the parent amino alcohols 1 by polymer bound triarylphosphine-I2 complex in anhydrous dichloromethane.

Direct conversion of oxiranes to alkenes by chlorotrimethylsilane and sodium iodide

Abstract Smooth and quantitative conversion of oxiranes to alkenes is achieved by treatment with in situ generated iodotrimethylsilane.

A new general synthesis of halohydrins

Abstract A new synthetic method has been devised for the rapid conversion of epoxides to chloro-, bromo- and iodo-hydrins in quantitative yield, under mild conditions and in the absence of protic acids.

Chiral N-protected β-iodoamines from α-aminoacids: a general synthesis

N-Protected d- or l-β-iodoamines (as 2), which are useful intermediates for the preparation of chiral β-aminoacids, are obtained smoothly from β-aminols (as I) in two steps and high yields.

Proline−β3-Amino-Ester Dipeptides as Efficient Catalysts for Enantioselective Direct Aldol Reaction in Aqueous Medium

Dipeptides obtained from l-proline and beta(3)-l-amino acids are reported to catalyze enantioselective direct aldol reaction in aqueous medium, leading to significant anti:syn diastereomeric ratios and enantiomeric excesses. The simple introduction of a polar substituent at the C-2 position of the beta(3)-l-amino acid was also found to enhance appreciably both diastereo- and enantioselectivity of the catalyst.

Diterpenes from Araucaria bidwilli

Abstract Eight diterpent acids of the labdane or clerodane type were obtained from the oleoresin of Araucaria bidwilli and characterized as their methyl esters.

Mild Synthesis of Protected α‐D‐Glycosyl Iodides

α-D-Glycosyl iodides are stereoselectively obtained by iodine replacement of the free anomeric hydroxyl group of fully protected sugars treated with a polymer bound triarylphosphane-iodine complex and imidazole. High yields and mild conditions, compatible with all the common protecting groups used in carbohydrate chemistry, characterize the conversion.

New diterpenes from Araucaria cunninghami

Abstract Eleven labdane diterpenes, nine of which are new compounds, were identified in the oleoresin of Araucaria cunninghami .

The reaction of ethanediyl S,S-acetals with halogens

Abstract Cyclic thioacetals and thioketals (1,3-dithiolanes) are reported to react smoothly with halogens in a 1:1 molar ratio, at room temperature in anhydrous carbon tetrachloride. The mechanistic aspects of the reaction are considered and evidence is shown of the intermediacy of monocationic rather than the previously postulated dicationic species in the cleavage reactions of 1,3-dithiolanes of aromatic ketones.

Polymer-Supported Phosphine-Halogen Complexes 41. Improved Formylation of Alcohols with Dimethylformamide

Abstract A new, very convenient procedure for smooth conversion of primary and secondary alcohols to their corresponding formic acid esters is described. This is based on the use of modified Vilsmeier Haak adducts, obtained from N, N-dimethylformamide and polymersupported triarylphosphine-halogen complexes.