Wehner JW, Lindhorst TK. S-Fluorenylmethyl protection of the cysteine side chain upon N(α)-Fmoc deprotection.
Beilstein J Org Chem 2012;
8:2149-55. [PMID:
23365626 PMCID:
PMC3555517 DOI:
10.3762/bjoc.8.242]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 11/01/2012] [Indexed: 01/21/2023] Open
Abstract
Deprotection of an N(α)-Fmoc-protected glycocysteine derivative 7 with an excess of morpholine unexpectedly led to the fluorenylmethyl-protected thioether 8 in high yield. The suggested mechanism for this reaction comprises the addition of the cysteine thiolate on the exocyclic double bond of dibenzofulvene, which is formed during Fmoc deprotection. The influence of base concentration on this transprotection reaction was studied.
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