Abstract
All four possible diastereoisomers of phosphinofer- rocenyloxazoline (Phosferrox type) ligands containing three elements of chirality were synthesized as single enantiomers. The S-c configured oxazoline moiety (R = Me, i-Pr) was used to control the generation of planar chirality by lithiation, with the alternative diastereoisomer formed by use of a deuterium blocking group. In each case subsequent addition of PhPCl2 followed by o-TolMgBr resulted in a single P-stereogenic diastereoisomer (S-c,S-p,S-phos and S-c,S-p,R-phos,R- respectively). The alternative diastereoisomers were formed selectively by addition of o-TolPCl(2) followed by PhMgBr ((S-c,S-p,R-phos and S-c,S-p,S-phos,S- respectively). Preliminary application of these four ligand diastereoisomers, together with (S-c,S-p) and (S-c,R-p) Phosferrox PPh2, to palladium catalyzed allylic alkylation of trans-1,3-diphenylallyl acetate revealed a stepwise increase/decrease in ee, with the configuration of the matched/matched diastereoisomer as S-c,S-p,S-phos (97% ee).
Original language | English |
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Pages (from-to) | 4838-4847 |
Number of pages | 10 |
Journal | Journal of Organic Chemistry |
Volume | 85 |
Issue number | 7 |
Early online date | 27 Feb 2020 |
DOIs | |
Publication status | Published - 3 Apr 2020 |
Keywords
- HIGHLY ENANTIOSELECTIVE HYDROGENATION
- DIPHOSPHINE LIGANDS
- ALLYLIC ALKYLATION
- PHOSPHINE OXIDES
- PLANAR CHIRALITY
- PHOSPHORUS
- KETONES
- COMPLEXES
- EFFICIENT
- VERSATILE
Profiles
-
Chris Richards
- School of Chemistry, Pharmacy and Pharmacology - Reader in Organic Chemistry
- Chemistry of Materials and Catalysis - Member
Person: Research Group Member, Academic, Teaching & Research