Synthesis 2020; 52(13): 1934-1946
DOI: 10.1055/s-0040-1707524
paper
© Georg Thieme Verlag Stuttgart · New York

Allyl 4-Chlorophenyl Sulfone as a Versatile 1,1-Synthon for Sequential α-Alkylation/Cobalt-Catalyzed Allylic Substitution

Tomoyuki Sekino
,
Shunta Sato
,
Kazuki Kuwabara
,
Koji Takizawa
,
,
Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12 Nishi-6, Kita-ku, Sapporo 060-0812, Japan   eMail: m-kojima@pharm.hokudai.ac.jp   eMail: smatsuna@pharm.hokudai.ac.jp
,
Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12 Nishi-6, Kita-ku, Sapporo 060-0812, Japan   eMail: m-kojima@pharm.hokudai.ac.jp   eMail: smatsuna@pharm.hokudai.ac.jp
› Institutsangaben
This work was supported in part by Japan Society for the Promotion of Science (JSPS KAKENHI Grant Number JP15H05802 in Precisely Designed Catalysts with Customized Scaffolding, JSPS KAKENHI Grant Number JP17H03049 and JP18H06097). T.S. thanks the Pharmaceutical Society of Japan for a fellowship (Nagai Memorial Research Scholarship).
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Publikationsverlauf

Received: 12. März 2020

Accepted after revision: 06. April 2020

Publikationsdatum:
27. April 2020 (online)


Abstract

Despite their unique potential as rare 1,1-dipole synthons, allyl sulfones are rarely used in target-oriented syntheses, likely due to the lack of a general catalytic method for their branch-selective allylic substitution. Herein, we identified allyl 4-chlorophenyl sulfone as a versatile linchpin for both base-mediated α-derivatization and subsequent cobalt-catalyzed allylic substitution. The sequential transformations allow for highly regioselective access to branched allylic substitution products with a variety of aliphatic side chains. The photoredox-enabled­ ­cobalt catalysis is indispensable for achieving high yields and regioselectivity­ for the desulfonylative substitution in contrast to traditional metal-catalyzed protocols, which lead to inferior outcomes in the corresponding transformations.

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