Biomedical subjects

E Mattmann

Publications and source records attributed to E Mattmann.

9 recordsLinked to original sources

PubMed2002

Synthesis of new tricyclic phosphines and phosphinites by intramolecular Diels-Alder reactions of trivalent phospholes.

Phospholes bearing an allyl-X substituent at phosphorus tend to undergo an intramolecular Diels-Alder cycloaddition (IMDA) leading to the corresponding tricyclic derivative. When X = O or NR, the IMDA easily takes place at room temperature. When X = CH2, the IMDA slowly takes place around 110-140 degrees C, as a function to the substitution pattern of the dienic system. Two tricyclic derivatives (X = O and CH2) have been characterized by X-ray crystal structure analysis of the P-sulfides.

Journal Article↗

PubMed2002

De-aromatizing phosphole.

Quantum-chemical DFT calculations using the B3LYP functionals have been carried out for 1-R-substitued phospholes and some 1-R-substitued 3,4-dimethylphospholes where R = H, Me, Ph, CN, OH, OMe, F, Cl, and Br. The aromaticity of the phospholyl rings is interpreted as a function of geometric, magnetic, and energetic indexes. It is shown, in agreement with previous experimental results, that phosphole aromaticity does not correlate with pyramidality at phosphorus. Variation of hyperconjugative and, to a lesser extent, conjugative effects is responsible for the change in cyclic delocalization for the phospholes studied here.

Journal Article↗

PubMed2001

Enhancing the dienic reactivity of phospholes: an improved access to trivalent 7-phosphanorbornenes.

A structural comparison of 1-cyano- and 1-alkoxy-3,4-dimethylphospholes with 1-benzylphosphole has led to some unexpected conclusions. There is no univocal relationship between phosphole aromaticity and pyramidality at phosphorus. It has been found that both the highly pyramidal 1-cyanophosphole 1 (sigma(CPC angles) = 290 degrees), and the much less pyramidal 1-alkoxyphosphole 6 (sigma(CPC angles) = 310 degrees) have a low Bird aromaticity index (27 for both molecules), when compared to 1-benzylphosphole (sigma(CPC angles) = 303 degrees, BI = 35.5). This low aromaticity is correlated with a high reactivity of the diene in both 1 and 7 (similar to 6) toward acrylonitrile. Good stereochemical control is observed with 7, which gives exclusively the anti,endo [4 + 2] cycloadducts with acrylonitrile and diethyl vinylphosphonate.

Journal Article↗

PubMed1982