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Asymmetric [2,3]-wittig rearrangement of oxygenated allyl benzyl ethers in the presence of a chiral di-tBu-bis(oxazoline) ligand: a novel synthetic approach to THF lignans.
Chemistry. 2009 Sep 28; 15(38):9911-7.C

Abstract

We have accomplished highly enantioselective [2,3]-Wittig rearrangements of functionalized allyl benzyl ethers in the presence of a chiral di-tBu-bis(oxazoline) ligand. In various oxygenated benzylic ethers, the reactions proceeded with excellent diastereo- and enantioselectivities, although the presence of a methoxy substituent at the ortho-position on the benzyl group drastically decreased the enantioselectivity. Conversely, o-ethyl and o-phenyl substituents had no significant effect on the selectivity. We found that the C2-substituent of the allylic moiety played an important role in producing high enantioselectivity. Highly enantioselective [2,3]-Wittig rearrangement in the presence of catalytic amounts of the chiral ligands is also described.

Authors+Show Affiliations

Faculty of Pharmacy, Osaka Ohtani University, 3-11-1 Nishikiori-Kita, Tondabayashi, Osaka 584-8540, Japan.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19697377

Citation

Kitamura, Maria, et al. "Asymmetric [2,3]-wittig Rearrangement of Oxygenated Allyl Benzyl Ethers in the Presence of a Chiral di-tBu-bis(oxazoline) Ligand: a Novel Synthetic Approach to THF Lignans." Chemistry (Weinheim an Der Bergstrasse, Germany), vol. 15, no. 38, 2009, pp. 9911-7.
Kitamura M, Hirokawa Y, Maezaki N. Asymmetric [2,3]-wittig rearrangement of oxygenated allyl benzyl ethers in the presence of a chiral di-tBu-bis(oxazoline) ligand: a novel synthetic approach to THF lignans. Chemistry. 2009;15(38):9911-7.
Kitamura, M., Hirokawa, Y., & Maezaki, N. (2009). Asymmetric [2,3]-wittig rearrangement of oxygenated allyl benzyl ethers in the presence of a chiral di-tBu-bis(oxazoline) ligand: a novel synthetic approach to THF lignans. Chemistry (Weinheim an Der Bergstrasse, Germany), 15(38), 9911-7. https://doi.org/10.1002/chem.200901212
Kitamura M, Hirokawa Y, Maezaki N. Asymmetric [2,3]-wittig Rearrangement of Oxygenated Allyl Benzyl Ethers in the Presence of a Chiral di-tBu-bis(oxazoline) Ligand: a Novel Synthetic Approach to THF Lignans. Chemistry. 2009 Sep 28;15(38):9911-7. PubMed PMID: 19697377.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Asymmetric [2,3]-wittig rearrangement of oxygenated allyl benzyl ethers in the presence of a chiral di-tBu-bis(oxazoline) ligand: a novel synthetic approach to THF lignans. AU - Kitamura,Maria, AU - Hirokawa,Yoshimi, AU - Maezaki,Naoyoshi, PY - 2009/8/22/entrez PY - 2009/8/22/pubmed PY - 2010/1/20/medline SP - 9911 EP - 7 JF - Chemistry (Weinheim an der Bergstrasse, Germany) JO - Chemistry VL - 15 IS - 38 N2 - We have accomplished highly enantioselective [2,3]-Wittig rearrangements of functionalized allyl benzyl ethers in the presence of a chiral di-tBu-bis(oxazoline) ligand. In various oxygenated benzylic ethers, the reactions proceeded with excellent diastereo- and enantioselectivities, although the presence of a methoxy substituent at the ortho-position on the benzyl group drastically decreased the enantioselectivity. Conversely, o-ethyl and o-phenyl substituents had no significant effect on the selectivity. We found that the C2-substituent of the allylic moiety played an important role in producing high enantioselectivity. Highly enantioselective [2,3]-Wittig rearrangement in the presence of catalytic amounts of the chiral ligands is also described. SN - 1521-3765 UR - https://www.unboundmedicine.com/medline/citation/19697377/Asymmetric_[23]_wittig_rearrangement_of_oxygenated_allyl_benzyl_ethers_in_the_presence_of_a_chiral_di_tBu_bis_oxazoline__ligand:_a_novel_synthetic_approach_to_THF_lignans_ L2 - https://doi.org/10.1002/chem.200901212 DB - PRIME DP - Unbound Medicine ER -