Synthesis 2018; 50(22): 4383-4394
DOI: 10.1055/s-0037-1610215
paper
© Georg Thieme Verlag Stuttgart · New York

Directed Zincation or Magnesiation of 2- and 4-Pyrones and Their Derivatives

Dorothée S. Ziegler
Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5–13, Haus F, 81377 München, Germany   Email: paul.knochel@cup.uni-muenchen.de
,
Lydia Klier
Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5–13, Haus F, 81377 München, Germany   Email: paul.knochel@cup.uni-muenchen.de
,
Nicolas Müller
Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5–13, Haus F, 81377 München, Germany   Email: paul.knochel@cup.uni-muenchen.de
,
Konstantin Karaghiosoff
Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5–13, Haus F, 81377 München, Germany   Email: paul.knochel@cup.uni-muenchen.de
,
Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5–13, Haus F, 81377 München, Germany   Email: paul.knochel@cup.uni-muenchen.de
› Author Affiliations
We would like to thank the Ludwig-Maximilians-University Munich for financial support. We thank Albemarle Corporation for the generous gift of chemicals and the SFB749 for financial support.
Further Information

Publication History

Received: 14 June 2018

Accepted after revision: 25 June 2018

Publication Date:
09 August 2018 (online)


Dedicated to Professor Scott Denmark on the occasion of his 65th birthday

Abstract

A regioselective magnesiation of the 2-pyrone scaffold was developed. Magnesiation of this heterocycle by using TMPMgCl·LiCl (TMP = 2,2,6,6-tetramethylpiperidyl) followed by trapping reactions with electrophiles such as aldehydes, allylic bromides, acid chlorides, and aryl iodides provided functionalized 2-pyrones. Furthermore, methyl coumalate and 3,5-dibromo-2H-pyran-2-one were zincated by using TMPZnCl·LiCl to afford zincated heterocycles, which reacted with typical electrophiles. A second magnesiation at position C3 of the 2-pyrone scaffold was achieved by using TMPMgCl·LiCl. Also, the zincation of the 4-pyrone scaffold at position C2 is reported, leading to functionalized 4-pyrones.

Supporting Information