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Please login to access the full content or check if you have access via3.10.3.1.1 Claisen Rearrangement/Intramolecular Carbonyl-Ene Reaction
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Jautze, S.; Peters, R., Science of Synthesis: Stereoselective Synthesis, (2011) 3, 464.
A catalytic, asymmetric, domino Claisen rearrangement/intramolecular carbonyl-ene reaction based on previous studies on the catalytic, asymmetric Claisen rearrangement (see Section 3.10.1.1.1) and on copper-catalyzed ene reactions[52] has been reported (Scheme 17).[53] The bis(4,5-dihydrooxazole) catalyst 2 promotes the formation of two new C—C bonds in almost quantitative yield and three stereocenters (two of which are quaternary) with excellent enantioselectivity and high catalyst-induced diastereocontrol. The reaction sequence proceeds via formation of an intermediate α-oxo ester 62 from enone precursor (E)-61. This intermediate is suitable for bidentate coordination to the chiral copper catalyst 2, thereby inducing an intramolecular carbonyl-ene reaction. The formation of two diastereomers 63A and 63B is a consequence of incomplete enantioselection in the Claisen rearrangement. Utilizing the isomeric substrate (Z)-61 with a Z-configured O-allyl moiety reverses the diastereomeric ratio.
Meeeee 88 Meeeee Meeeeee Meeeeeeeeeeee/Meeeeeeeeeeeee Meeeeeee-Mee Meeeeeee[88]
| Meeeee ee 88 | Meeee (88M/88M) | ee (%) ee Meeee Meeeeeeeeeee | Meeee (%) | Mee |
|---|---|---|---|---|
| M | 88:88 | 88 | 88 | [88] |
| M | 88:88 | 88 | 88 | [88] |
References
| [52] | Meeee, M. M.; Meeeee, M. M.; Meeeee, M. M.; Meeee, M. M.; Meeeeeeee, M., M. Me. Meee. Mee., (8888) 888, 8888. |
| [53] | Meeee, M.; Meeeeeeeee, M., Meeeeee, (8888), 8888. |
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