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Abstract The biological and therapeutic significance of natural products is a powerful impetus for the development of efficient methods to facilitate their construction. Accordingly, and reflecting the prevalence of β‐oxy‐carbonyl motifs, a sophisticated arsenal of aldol‐based strategies has evolved that is contingent on the generation of single enolate isomers. Since this has the potential to compromise efficiency in reagent‐based paradigms, direct catalysis‐based solutions would be enabling. To complement the array of substrate‐based strategies, and regulate enolate geometry at the catalyst level, a direct catalytic alkylation of esters with oxyallenes has been developed. Synergizing metal hydride reactivity with Lewis base catalysis has resulted in a broad reaction scope with useful levels of stereocontrol (up to >99 %ee). Facile derivatization of these ambiphilic linchpins is demonstrated, providing access to high‐valuevicinalstereocenter‐containing motifs, including 1,2‐amino alcohols.
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Oxyphosphonium Enolate Equilibria in a (4+1)‐Cycloaddition Approach toward Quaternary C3‐Spirooxindole Assembly
Abstract An efficient and convergent (4+1)‐cycloaddition strategy toward the construction of spirooxindole benzofurans that involves the intermediacy of an isatin‐derived oxyphosphonium enolate is presented. Mechanistic investigations employing in situ NMR analysis of the reaction mixture revealed a correlation between phosphonium enolate structure and product distribution that was heavily influenced by the solvent and reaction temperature.
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- Award ID(s):
- 1956170
- PAR ID:
- 10250172
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Chemistry – A European Journal
- Volume:
- 27
- Issue:
- 40
- ISSN:
- 0947-6539
- Format(s):
- Medium: X Size: p. 10349-10355
- Size(s):
- p. 10349-10355
- Sponsoring Org:
- National Science Foundation
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