Farah AO, Rabah M, Beng TK. Transition metal-free domino acyl substitution/Michael addition of alkenyl Grignard reagents to lactam esters: synthesis of lactam-bearing homoallylic ketones.
RSC Adv 2020;
10:22454-22459. [PMID:
35514603 PMCID:
PMC9054586 DOI:
10.1039/d0ra03885g]
[Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/07/2020] [Indexed: 11/21/2022] Open
Abstract
A solvent-controlled protocol for the direct and transition metal-free addition of alkenyl Grignard reagents to vicinally functionalized sp3-rich morpholinones has been developed, leading to the chemo and regioselective synthesis of lactam-bearing homoallylic ketones. The addition of lithium chloride proved to be essential. In cases where a new stereocenter is generated, the doubly branched homoallylic ketones are obtained in unexpectedly high diastereoselectivities. Efforts to extend the methodology to other heterosubstituted lactams revealed some important reactivity and selectivity differences.
A solvent-controlled and heteroatom-dictated protocol for the transition metal-free addition of alkenyl Grignard reagents to lactam esters has been developed, leading to the chemo- and regioselective synthesis of lactam-tethered homoallylic ketones.![]()
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