Tkachenko IM, Mankova PA, Rybakov VB, Golovin EV, Klimochkin YN. Wagner-Meerwein type rearrangement in 5-oxohomoadamantane series.
Org Biomol Chem 2020;
18:465-478. [PMID:
31845947 DOI:
10.1039/c9ob02060h]
[Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Efficient methods for introducing various substituents into the α-position of ethyl 5-oxohomoadamantyl-4-carboxylate are reported. An unexpected acid-catalysed 1,2-alkyl shift in the series of synthesized α,α-bis-substituted 5-oxohomoadamantanes, and also in the hydroxy derivatives of homoadamantane was found. Such a retropinacol-like rearrangement leads to tetra- or pentacyclic mono- or bis-lactones containing a homoadamantane moiety. This new transformation opens access to the synthesis of previously unknown 2,4-di and 2,3,4-trisubstituted derivatives of homoadamantane. The resulting caged γ-butyro- and δ-valerolactones could be considered as potential synthetic or metabolic precursors of conformationally restricted GABA and δ-aminovaleric acid analogues.
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