Bicyclo[2.2.2]octane-derived chiral ligands-synthesis and application of BODOLs in the asymmetric reduction of acetophenone with catecholborane
Författare
Summary, in English
An improved synthetic route to the bicyclo[2.2.2]octane-2,6-diol ligands (2,6-BODOLS) allowed an increased structural variation of the ligand side-arm. The addition of aromatic or vinylic Grignard reagents to hydroxyketone 1 was highly selective and ligands 3f-3I were isolated in 84-97% yield. The addition of alkyl Grignard reagents containing beta-hydrogens resulted in lower yields (13-71%) due to competing ketone reduction. A number of 2,5-BODOLs were synthesized using a similar methodology. The ligands, together with Ti(OiPr)(4), were tested in the asymmetric reduction of acetophenone with catecholborane (up to 98% ee). 1-Naphthyl-BODOL 3i was employed as an allylboration reagent to benzaldehyde together with Sc(OTf)(3), resulting in (1S)-1-phenyl-3-buten-1-ol in 80% ee. (C) 2008 Elsevier Ltd. All rights reserved.
Avdelning/ar
Publiceringsår
2008
Språk
Engelska
Sidor
1765-1777
Publikation/Tidskrift/Serie
Tetrahedron: Asymmetry
Volym
19
Issue
15
Dokumenttyp
Artikel i tidskrift
Förlag
Elsevier
Ämne
- Organic Chemistry
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 0957-4166