Lombard FJ, Lepage RJ, Schwartz BD, Johnston RC, Healy PC, Krenske EH, Coster MJ. Synthesis of spirocyclic orthoesters by 'anomalous' rhodium(ii)-catalysed intramolecular C-H insertions.
Org Biomol Chem 2018;
16:256-261. [PMID:
29239449 DOI:
10.1039/c7ob02123b]
[Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A tetrahydropyranyl acetal bearing a proximal phenyl diazoketone substituent underwent Rh(ii)-catalysed C-H insertion via an 'anomalous' C-O bond-forming, rather than C-C bond-forming, transformation, giving spirocyclic orthoesters. Density functional theory calculations with M06 show that the formation of these anomalous products involves hydride transfer to the rhodium carbene, giving an intermediate zwitterion which undergoes C-O bond formation in preference to C-C bond formation.
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