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DOI: 10.1055/s-0035-1561627
Iron-Catalyzed Reductive Metalation–Allylation and Metalative Cyclization of 2,3-Disubstituted Oxetanes and Their Stereoselectivity
Publikationsverlauf
Received: 14. März 2016
Accepted after revision: 31. März 2016
Publikationsdatum:
12. Mai 2016 (online)
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Abstract
A novel process for the reductive magnesiation of 2-substituted oxetanes and the metalative cyclization of ω-alkynyl oxetanes is developed using n-propylmagnesium chloride in the presence of an iron catalyst. The generated intermediate organomagnesium compounds react with electrophiles. The reactions of 2,3-disubstituted oxetanes and their subsequent allylation with allyl halides in the presence or absence of copper(I) cyanide as the catalyst is studied with a unique switching of stereoselectivity being observed in the absence or presence of copper(I) cyanide . In addition, it is found that the metalative cyclization of 3-substituted 2-alkynyl oxetanes proceeds in an anti-selective manner starting from both syn- and anti-substrates. In all cases, the stereochemistry at the 2-position of the oxetanes is lost during the reactions suggesting the involvement of a radical process.
Key words
iron catalyst - oxetanes - reductive magnesiation - metalative cyclization - (3-oxidopropyl)magnesium - diastereoselective reactionSupporting Information
- Supporting information for this article is available online at http://dx.doi.org/10.1055/s-0035-1561627.
- Supporting Information
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For Fe-catalyzed Csp3–O bond cleavage and subsequent Csp3–Csp3 bond formation, see:
For examples of Fe-catalyzed C–O bond cleavage reactions, see:
For a Mn-catalyzed reaction, see: