Projects per year
Abstract
Starting from (η5-acetylcyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt(I), highly enantioselective (99 % ee) (S)-CBS catalysed ketone reduction followed by stereospecific alcohol-azide exchange, azide reduction and dimethyllation gave (R)-(η5-α-N,N-dimethylaminoethylcyclopentadienyl)(η4-tetraphenylcyclobutadiene) cobalt(I) (Arthurs’ amine). This underwent highly diastereoselective cyclopalladation to give di-μ-acetate-bis-(R)-[(η5-(Sp)-2-(α-N,N-dimethylaminoethyl)cyclopentadienyl, 1-C, N)(η4-tetraphenylcyclobutadiene)cobalt(I)]dipalladium, and highly diastereoselective lithiation to give (R)-(η5-(Sp)-1-(α-N,N-dimethylaminoethyl)-2-(diphenylphosphino)cyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt(I) (PPCA) following the addition as electrophile of chlorodiphenylphosphine. This PN-ligand was converted into (R)-(η5-(Sp)-1-(α-dicyclohexylphosphinoethyl)-2-(diphenylphosphino)cyclopentadienyl)(η4-tetraphenylcyclobutadiene)cobalt(I), a PP-ligand (Rossiphos), by stereospecific amine-phosphine exchange using HPCy2. These air-stable P−N and P−P complexes are the first examples of a new class of bulky planar chiral ligands for application in asymmetric catalysis.
Original language | English |
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Pages (from-to) | 4310-4319 |
Number of pages | 10 |
Journal | Chemistry - A European Journal |
Volume | 24 |
Issue number | 17 |
Early online date | 1 Feb 2018 |
DOIs | |
Publication status | Published - 20 Mar 2018 |
Keywords
- cobalt
- sandwich complexes
- ligands
- diastereoselectivity
- enantioselectivity
Profiles
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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
Projects
- 1 Finished
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Catalyst Diversity from Chiral Palladacycles
Engineering and Physical Sciences Research Council
1/06/16 → 31/05/19
Project: Research