Novel asymmetric photodimerization reaction of coumarin derivatives bearing a chiral 2-oxazolidinone auxiliary

Kennosuke Itoh; Fumiya Odate; Takuma Karikomi; Keishi Obe; Tsutomu Miyamori; Hideaki Kamiya; Kenji Yoza; Kenichiro Nagai; Hideaki Fujii; Hiroyuki Suga; Ken Tokunaga

doi:10.1039/c9ra00822e

Novel asymmetric photodimerization reaction of coumarin derivatives bearing a chiral 2-oxazolidinone auxiliary

RSC Adv. 2019 Apr 23;9(22):12365-12369. doi: 10.1039/c9ra00822e. eCollection 2019 Apr 17.

Authors

Kennosuke Itoh^{1

2}, Fumiya Odate³, Takuma Karikomi⁴, Keishi Obe⁵, Tsutomu Miyamori⁶, Hideaki Kamiya⁶, Kenji Yoza⁷, Kenichiro Nagai², Hideaki Fujii^{1

2}, Hiroyuki Suga⁶, Ken Tokunaga⁸

Affiliations

¹ Laboratory of Medicinal Chemistry, School of Pharmacy, Kitasato University 5-9-1 Shirokane, Minato-ku Tokyo 108-8641 Japan itok@pharm.kitasato-u.ac.jp.
² Medicinal Research Laboratories, School of Pharmacy, Kitasato University 5-9-1 Shirokane, Minato-ku Tokyo 108-8641 Japan.
³ Applied Chemistry and Chemical Engineering Program, Graduate School, Kogakuin University 2665-1 Nakano Hachioji Tokyo 192-0015 Japan.
⁴ Department of Applied Chemistry, Faculty of Engineering, Kogakuin University 2665-1 Nakano Hachioji Tokyo 192-0015 Japan.
⁵ Department of Applied Chemistry, School of Advanced Engineering, Kogakuin University 2665-1 Nakano Hachioji Tokyo 192-0015 Japan.
⁶ Department of Materials Chemistry, Faculty of Engineering, Shinshu University 4-17-1 Wakasato Nagano 380-8553 Japan.
⁷ Bruker Japan 3-9, Moriya-cho, Kanagawa-ku Yokohama 221-0022 Japan.
⁸ Division of Liberal Arts, Center for Promotion of Higher Education, Kogakuin University 2665-1 Nakano Hachioji Tokyo 192-0015 Japan.

Abstract

A novel asymmetric photodimerization reaction of coumarin derivatives bearing the (S)-4-benzyl-2-oxazolidinone auxiliary provides only the syn-head-to-tail (syn-HT) dimer with moderate diastereoselectivity (up to 75 : 25). The mechanism of complete syn-HT selectivity and moderate diastereoselectivity is proposed based on the result of density functional theory (DFT) calculation. The benzyl group of the (S)-4-benzyl-2-oxazolidinone auxiliary in combination with a Lewis acid exerts effective diastereofacial shielding of the reaction site.