Study on Stereocontrol in Sigmatropic Rearrangement

• Project/Area Number: 01540455
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 天然物有機化学
• Research Institution: Kyushu University
• Principal Investigator: KATSUKI Tsutomu Kyushu University, Fac. of Sci., Professor, 理学部, 教授 (40037271)
• Project Period (FY): 1989 – 1990
• Project Status: Completed (Fiscal Year 1990)
• Budget Amount: ¥1,700,000 (Direct Cost: ¥1,700,000); Fiscal Year 1990: ¥200,000 (Direct Cost: ¥200,000); Fiscal Year 1989: ¥1,500,000 (Direct Cost: ¥1,500,000)
• Keywords: Sigmatropic Rearrangement / [2, 3] Winttig Rearrangement / Kinetic Resolution / Concave-shaped Ligand / 〔2.3〕Wittig転位反応 / ボ-ト型遷移状態 / 複合ルイス酸 / 〔2,3〕Wittig転位反応 / アンチ選択性

Research Abstract

i) Anti-selective [2, 3] Wittig rearrangement
In the course of the study on stereocontrol of sigmatropic rearrangements, we found that [2, 3] Wittig rearrangement of 2' -heterosubstituted alpha-alkenyloxyacetic acid esters exhibited unusual anti-selectivity as shown below. The origin of this unusual stereoselectivity was attributed to the steric repulsion of a ligand on the counter metal ion and a C2' -substituent and to interaction of lone pair orbital on oxygen atom and sigma^* -orbital of C2 -carbon and hetero atom bond.
ii) Preparation of concave-shaped ligands and their application to kinetic resolution of dl-epoxy alcohols.
Concave-shaped ligands (1 and 2) were prepared from L-alanine and their titanium complexes were used for kinetic resolution of dl-epoxy alcohols as Lewis acid catalyst. As shown in the following scheme, kinetic resolution of 3, 3-disubstituted epoxy alcohols using a combination of Ti (OPr^i) 4 and 1a was found to proceed with high efficiency.
Further study on ester enolate Claisen rearrangement via titanium enolate wherein titanium ion carries 1 as a ligand, is under investigation.

Research Products

• [Publications] 石川 彰: "Stereoelectronically Controlled [2,3]ーWitting Rearrangement of Isopropyl 2^´ーHeterosubstituted 2^´ーAlkenyloxyloxyacetates" Tetrahedron Letters. 31. 2415-2418 (1990)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] 石川 彰: "Kinetic Resolution of dlー2,3ーEpoxy Alcohols Using Chiral Titanium Complex with Amino Alcohol Derived Ligand" Tetrahedron Letters.
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] A. Ishikawa, H. Uchiyama, T. Katsuki, and M, Yamaguchi: "Stereoelectronically Controlled [2, 3] Wittig Rearrangement of Isopropyl 2' -Heterosubstituted- 2' -Alkenyloxyacetates" Tetrahedron Letters. 31-17. 2415-2418 (1990)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] A. Ishikawa and T. Katsuki: "Kinetic Resolution of dl-2, 3-Epoxy Alcohols Using Chiral Titanium Complex with Amino Alcohol Derived Ligand"
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] 石川 彰: "Stereoelectronically Controlled [2,3]Wittig Rearrangement of Isopropyl 2^1ーHeterosubstituted 2^1ーAlkenyloxyacetates" Tetrahedron Letters. 31. 2415-2418 (1990)
• [Publications] 石川 彰: "Kinetic Resolution of dlー2,3ーEpoxy Alcohols Using Chiral Titanium Complex with Amino Alcohol Derived Ligand" Tetrahedron Letters.
• [Publications] 石川彰: "Sterically Controlled[2,3]Wittig Rearrangement of Isopropyl 2'-Heterosubstituted-2'-alkenyloxyacetates" Tetrahedron Letters.