Stereoselective synthesis of o-bromo (or iodo)aryl P-chirogenic phosphines based on aryne chemistry.
The efficient synthesis of chiral or achiral tertiary phosphines bearing an o-bromo (or iodo)aryl substituent is described. The key step of this synthesis is based on the reaction of a secondary phosphine borane with the 1,2-dibromo (or diiodo)arene, owing to the formation in situ of an aryne species in the presence of n-butyllithium. When P-chirogenic secondary phosphine boranes were used, the corresponding o-halogeno-arylphosphine boranes were obtained without racemization in moderate to good yields and with ee up to 99%. The stereochemistry of the reaction, with complete retention of the configuration at the P atom, has been established by X-ray structures of P-chirogenic o-halogenophenyl phosphine borane complexes. The decomplexation of the borane was easily achieved without racemization using DABCO to obtain the free o-halogeno-arylphosphines in high yields.
Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB-StereochIM-UMR CNRS 6302), 9 avenue A. Savary BP47870, 21078 Dijon Cedex, France.
Jérôme
J
Bayardon
Hugo
H
Laureano
Vincent
V
Diemer
Mathieu
M
Dutartre
Utpal
U
Das
Yoann
Y
Rousselin
Jean-Christophe
JC
Henry
Françoise
F
Colobert
Frédéric R
FR
Leroux
Sylvain
S
Jugé