Isomerisations of cycloalkene- and bicycloalkene-derived achiral epoxides by enantioselective alpha-deprotonation

Journal article

Enantioselective α-deprotonation-rearrangement of cis-cyclooctene oxide 1 using organolithiums in the presence of (-)-sparteine 4 or (-)-α-isosparteine 5 gives the (-)-alcohol 2 in good yields and ees. The use of C2-symmetric bisoxazolines (-)-6a-d as ligands allows access to the (+)-alcohol 2. (-)-α-Isosparteine 5 functions as an efficient asymmetric ligand catalyst in the rearrangement of 1. The α-deprotonation process can be extended to other cycloalkene-derived achiral epoxides 7, 9, 11, 15 and 19. Lithium amide-induced transformations of rigid bicycloalkene-derived epoxides (25, 34 and 42) are described, providing insight into the rearrangement mechanisms which operate following α-lithiation in such systems. The enantioselective α-deprotonation-rearrangement of bicycloalkene-derived epoxides (25, 29 and 42) to ketones (28, 33 and 44 respectively) is described.

Authors: Hodgson, D; Lee, G; Marriott, R; Thompson, A; Wisedale, R

• Publication status: Published
• Journal: JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1
• Issue: 14
• Pages: 2151-2161
• Publication date: 1998-07-21
• DOI: 10.1039/a802434k
• EISSN: 1364-5463
• ISSN: 0300-922X
• Language: English