First prebiotic generation of a ribonucleotide from adenine, D-ribose and trimetaphosphate.

Adenosine monophosphate isomers are obtained by self-assembling of adenine, D-ribose and trimetaphosphate in aqueous solution in good yields. This generation of a ribonucleotide from its three molecular components occurs in a one-pot reaction at room temperature for about 30-40 days and with high chemio-, regio-, and stereo-selectivity. Similar results are obtained with guanine. A mechanism is also proposed.

The role played by phosphorus hexacoordination in driving the stereochemical outcome of a phosphination reaction.

Asymmetric alkyl phospholanes have been diastereoselectively synthesized by addition of an unsymmetrical bis-Grignard reagent and of a mono-Grignard reagent to benzothiadiphosphole (1) and isolated as sulfides. The relative cis/trans ratio of the products depends on the steric hindrance of the mono-Grignard used. An accurate analysis of NMR and stereoselective data revealed the fundamental role played by hexacoordinated phosphorus intermediates in driving the stereochemical outcome of the reaction. The particular bicyclic and folded structure of reagent 1 strongly stabilizes hypercoordinated phosphorus species involved in the reaction and favors their formation. Pentacoordinate and metastable hexacoordinate phosphorus species have been detected and their evolution studied through (31)P NMR spectroscopy. The diastereoselective outcome of the reaction between reagent 1 and the couple bis-Grignard reagent 5/mono-Grignard reagent has been explained through a pathway involving hexacoordination of the phosphorus as a key step.

High atom-economical one-pot synthesis of secondary phosphines and their borane complexes using recycling phosphorus donor reagent.

[reaction: see text] A general new method for the one-pot preparation of secondary phosphines 11 and in situ generation of their borane complexes 12 is described. This method consists of the sequential addition, at room temperature, of equivalent amounts of R(1)MgBr and R(2)MgBr to 1 equiv of the phosphorus atom donor reagent 1. Final treatment with water gives secondary phosphines R(1)R(2)PH (or the corresponding phosphine-borane complexes if treated with BH(3).THF) and the end product 6, which can be recycled.

Highly atom-economic one-pot formation of three different C-P bonds: general synthesis of acyclic tertiary phosphine sulfides.

The reaction of benzothiadiphosphole 1 with an equimolar mixture of R1MgBr and R2MgBr gave intermediate A', which, after only 4-5 min, was treated with an equimolar amount of R3MgBr, giving the asymmetric phosphine PR1R2R3 in 45% overall yield (75-80% yield when R1 = R2 and 85-90% yield when R1 = R2 = R3) and the byproduct 6 in 90% yield. The treatment of 6 with PCl3 quantitatively regenerates the starting reagent 1. Treatment of the phosphines with elemental sulfur gave the corresponding sulfides.

Solvent-free reaction of some 1,2-diaza-1,3-butadienes with phosphites: environmentally friendly access to new diazaphospholes and E-hydrazonophosphonates.

[structures: see text] The present article describes the reaction between 1,2-diaza-1,3-butadienes and trialkyl phosphites, under an atmosphere of nitrogen and under solvent-free conditions, to give alkyl 3,3-dialkoxy-2H-1,2,3lambda5-diazaphosphole-4-carboxylates that, in turn, are converted into corresponding E-hydrazonophosphonates by treatment with THF:water (95:5). These latter compounds are obtained directly by the reaction of 1,2-diaza-1,3-butadienes with trialkyl phosphites in the presence of air. These compounds are useful for the further preparation of dialkyl (5-methyl-3-oxo-2,3-dihydro-1H-4-pyrazolyl)phosphonates and 2-dialkoxyphosphoryl-1,2,3-thiadiazoles.