Premium
Diastereofacial Selectivity of O ‐Protected α‐Hydroxy Aldehydes: Temperature and Solvent Effect
Author(s) -
Cainelli Gianfranco,
Giacomini Daria,
Galletti Paola,
Orioli Paolo,
Paradisi Francesca
Publication year - 2000
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200011)2000:21<3619::aid-ejoc3619>3.0.co;2-9
Subject(s) - chemistry , selectivity , enthalpy , diastereomer , stereoselectivity , solvent , solvent effects , thermodynamics , entropy (arrow of time) , computational chemistry , organic chemistry , catalysis , physics
Temperature dependence measurements allow the evaluation of stereoselectivity in terms of differential enthalpy and entropy of activation. An analysis of diastereoselectivity in the addition reaction of n BuLi to O ‐protected α‐hydroxy aldehydes revealed the great importance of the entropic contribution in directing the facial diastereoselectivity. In many cases, the resulting Eyring plots show an inversion temperature ( T inv ). The existence of the T inv as well as the enthalpic and entropic dominance of one diastereoisomer greatly depend on the reaction solvent.