Residual stereoisomerism is a form of stereoisomerism discovered by Mislow in the seventies which does not involve any rigid stereogenic element. Chirality is due to the activation of a preferred stereomerization process.1 In light of possible applications of residual enantiomers as ligands for transition metals in stereoselective reactions, some C3 phosphanes and phosphane oxides which could exist as residual antipodes were synthesized. Compounds 1 and 2 are examples of this kind of molecules. Some of them were obtained in an enantiopure state, structurally characterized and absolute configuration descriptors suggested. Configurational stability of residual enantiomers was assessed by CD decay and DNMR spectroscopy.2 The influence of steric and electronic properties on configurational stability has been investigated. Phosphane oxides display a much higher configurational stability than the corresponding phosphanes. In particular, the first tris-arylphosphane (2, X= lone pair) existing as residual enantiomer was obtained in an enantiopure state.
Designing chiral monodentate ligands devoid of rigid stereogenic elements : the residual enantiomers of C3 symmetric P-centered propeller / T. Benincori, R. Cirilli, M. Pierini, T. Pilati, S. Rizzo, F. Sannicolò. ((Intervento presentato al 9. convegno Congresso del Gruppo Interdivisionale di Chimica Organometallica della Società Chimica Italiana tenutosi a Firenze nel 2010.
Designing chiral monodentate ligands devoid of rigid stereogenic elements : the residual enantiomers of C3 symmetric P-centered propeller
F. SannicolòUltimo
2010
Abstract
Residual stereoisomerism is a form of stereoisomerism discovered by Mislow in the seventies which does not involve any rigid stereogenic element. Chirality is due to the activation of a preferred stereomerization process.1 In light of possible applications of residual enantiomers as ligands for transition metals in stereoselective reactions, some C3 phosphanes and phosphane oxides which could exist as residual antipodes were synthesized. Compounds 1 and 2 are examples of this kind of molecules. Some of them were obtained in an enantiopure state, structurally characterized and absolute configuration descriptors suggested. Configurational stability of residual enantiomers was assessed by CD decay and DNMR spectroscopy.2 The influence of steric and electronic properties on configurational stability has been investigated. Phosphane oxides display a much higher configurational stability than the corresponding phosphanes. In particular, the first tris-arylphosphane (2, X= lone pair) existing as residual enantiomer was obtained in an enantiopure state.Pubblicazioni consigliate
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