Starting from the inexpensive 2,2-difluoro-1,3-benzodioxole or its 5-bromo deriv., two new atropisomeric bisphosphines have been prepd. which, after racemate resoln., exhibit attractive features as ligands for enantioselective catalysts. The key step in their synthesis is a low temp. Ullmann reaction. An improved protocol secures coupling yields of 70-80%. For example, the treatment of 5,5-dibromo-2,2,2',2'-tetrafluoro[4,4'-bi-1,3-benzodioxole] with diphenylphosphinous chloride gave (2,2,2',2'-tetrafluoro[4,4'-bi-1,3-benzodioxole]-5,5'-diyl)bis[diphenylphosphine] (I). The resoln. of I was not reported. The application of (+)-I and (-)-I was previously reported. [on SciFinder (R)]
Title
Atropisomeric biarylbisphosphines derived from 2,2-difluoro-1,3-benzodioxole
Published in
Synthesis
Issue
3
Pages
326-328
Date
2004
ISSN
0039-7881
Note
CAN 140:357430
29-7
Organometallic and Organometalloidal Compounds
Institut de Chimie moleculaire et biologique, Batiment de Chimie (BCh),Ecole polytechnique federale,Lausanne,Switz.
Journal
written in English.
1079-66-9 (Diphenylphosphinous chloride); 33070-32-5 (5-Bromo-2,2-difluoro-1,3-benzodioxole); 663934-00-7 (-2,2-Difluoro-4-(triethylsilyl)-1,3-benzodioxole); 663934-09-6 (6-Bromo-2,2-difluoro-4-(triethylsilyl)-1,3-benzodioxole) Role: RCT (Reactant), RACT (Reactant or reagent) (prepn. of atropisomeric (tetrafluoro[bi-1,3-benzodioxole]diyl)bis[diphenylphosphine] derivs.); 663934-10-9P; 681136-90-3P; 681136-91-4P; 681136-92-5P; 681136-93-6P; 681136-94-7P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. of atropisomeric (tetrafluoro[bi-1,3-benzodioxole]diyl)bis[diphenylphosphine] derivs.); 681136-95-8P; 681259-24-5P Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of atropisomeric (tetrafluoro[bi-1,3-benzodioxole]diyl)bis[diphenylphosphine] derivs.)
Record creation date
2006-03-03
