Synthesis of Neoglycoconjugates by the Desulfurative Rearrangement of Allylic Disulfides
作者:David Crich、Fan Yang
DOI:10.1021/jo8015314
日期:2008.9.19
neoglycosyl donors are prepared on the basis of connection of an allylicdisulfide motif to the anomeric center via a simple O-glycosyl linkage or N-glycosyl amide unit. Conjugation of both sets of donors to cysteine in peptides is demonstrated through classical disulfide exchange followed by the phosphine-mediated desulfurative allylicrearrangement resulting in neoglycopeptides characterized by a simple thioether
DECHALCOGENATIVE METHODS FOR THE PREPARATION OF ALLYLIC SULFIDES
申请人:Crich David
公开号:US20100222549A1
公开(公告)日:2010-09-02
A dechalcogenative method for the preparation of an allylic sulfide comprises contacting an activated chalcogenide of Formula (I) with a thiol of Formula (II) for a period of time sufficient to form an intermediate of Formula (III), and supplying sufficient activation energy to the intermediate of Formula (III), in a suitable solvent, preferably in the absence of a phosphine or other thiophile, to induce a [2,3]-sigmatropic rearrangement therein to form an allylic sulfide of Formula (IV), with concomitant loss of chalcogen Z, as set forth in the following reaction scheme, wherein X is an activating group selected from the group consisting of CN, S-pyridyl, S-heteroaryl, SO2-aryl, and SO3Y; Y is an alkali metal ion; Z is Se or S; R1, R2, R3, R4, and R5 are each independently H or a hydrocarbon moiety; and R is an organic moiety.
Dechalcogenative Allylic Selenosulfide and Disulfide Rearrangements: Complementary Methods for the Formation of Allylic Sulfides in the Absence of Electrophiles. Scope, Limitations, and Application to the Functionalization of Unprotected Peptides in Aqueous Media
作者:David Crich、Venkataramanan Krishnamurthy、Franck Brebion、Maheswaran Karatholuvhu、Venkataraman Subramanian、Thomas K. Hutton
DOI:10.1021/ja072969u
日期:2007.8.1
Primary allylic selenosulfates (seleno Bunte salts) and selenocyanates transfer the allylic selenide moiety to thiols giving primary allylic selenosulfides, which undergo rearrangement in the presence of PPh3 with the loss of selenium to give allylically rearranged allyl alkylsulfides. This rearrangement may be conducted with prenyl-type selenosulfides to give isoprenyl alkylsulfides. Alkyl secondary