Iron-Catalyzed Reductive Metalation-Allylation and Metalative Cyclization of 2,3-Disubstituted Oxetanes and Their Stereoselectivity

A novel process for the reductive magnesiation of 2-substituted oxetanes and the metalative cyclization of omega-alkynyl oxetanes is developed using n-propylmagnesium chloride in the presence of an iron catalyst. The generated intermediate organomagnesium compounds react with electrophiles. The reac...

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Bibliographic Details
Published inSynthesis (Stuttgart) Vol. 48; no. 17; pp. 2823 - 2828
Main Authors Sugiyama, Yu-ki, Heigozono, Shiori, Tamura, Kazuhiro, Okamoto, Sentaro
Format Journal Article
LanguageEnglish
Published STUTTGART Thieme Medical Publishers 01.09.2016
Subjects
Chemistry
Chemistry, Organic
Physical Sciences
Science & Technology
(3-oxidopropyl) magnesium
metalative cyclization
reductive magnesiation
diastereoselective reaction
oxetanes
ADDITIONS
iron catalyst
TETRAHYDROFURAN
GRIGNARD-REAGENTS
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Summary:A novel process for the reductive magnesiation of 2-substituted oxetanes and the metalative cyclization of omega-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.
ISSN:0039-7881
1437-210X
DOI:10.1055/s-0035-1561627