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Development of an efficient procedure for indole ring synthesis from 2-ethynylaniline derivatives catalyzed by CuII salts and its application to natural product synthesis.
J Org Chem. 2004 Feb 20; 69(4):1126-36.JO

Abstract

The development of efficient methods for the indole synthesis catalyzed by Cu(II) salts and its applications were investigated. Cu(OAc)(2) has been proved to be the best catalyst for the synthesis of various 1-p-tolylsulfonyl or 1-methylsulfonylindoles, which have both electron-withdrawing and electron-donating groups on the aromatic ring and C2 position of indoles. For the primary aniline derivatives, Cu(OCOCF(3))(2) showed good activities, while Cu(OAc)(2) was a good catalyst for the cyclization of secondary anilines. This methodology could be applied to the sequential cyclization reaction for the compounds which have the electrophilic part in the same molecule. By prior treatment with KH, the sequential cyclization was realized to provide the tricyclic ring systems, but it was limited to five- and six-membered rings for the second cyclization. Finally, formal and total synthesis of hippadine with the Cu(II)-promoted indole synthesis as the key step was accomplished.

Authors+Show Affiliations

Hiroya K
Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku, Sendai 980-8578, Japan. hiroya@mail.tains.tohoku.ac.jp
Itoh S
No affiliation info available
Sakamoto T
No affiliation info available

MeSH

AcetyleneAlkaloidsAmaryllidaceae AlkaloidsAniline CompoundsBiological FactorsCopperCyclizationIndolesMolecular Structure

Pub Type(s)

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

Language

eng

PubMed ID

14961661

Citation

Hiroya, Kou, et al. "Development of an Efficient Procedure for Indole Ring Synthesis From 2-ethynylaniline Derivatives Catalyzed By CuII Salts and Its Application to Natural Product Synthesis." The Journal of Organic Chemistry, vol. 69, no. 4, 2004, pp. 1126-36.
Hiroya K, Itoh S, Sakamoto T. Development of an efficient procedure for indole ring synthesis from 2-ethynylaniline derivatives catalyzed by CuII salts and its application to natural product synthesis. J Org Chem. 2004;69(4):1126-36.
Hiroya, K., Itoh, S., & Sakamoto, T. (2004). Development of an efficient procedure for indole ring synthesis from 2-ethynylaniline derivatives catalyzed by CuII salts and its application to natural product synthesis. The Journal of Organic Chemistry, 69(4), 1126-36.
Hiroya K, Itoh S, Sakamoto T. Development of an Efficient Procedure for Indole Ring Synthesis From 2-ethynylaniline Derivatives Catalyzed By CuII Salts and Its Application to Natural Product Synthesis. J Org Chem. 2004 Feb 20;69(4):1126-36. PubMed PMID: 14961661.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Development of an efficient procedure for indole ring synthesis from 2-ethynylaniline derivatives catalyzed by CuII salts and its application to natural product synthesis. AU - Hiroya,Kou, AU - Itoh,Shin, AU - Sakamoto,Takao, PY - 2004/2/14/pubmed PY - 2004/4/24/medline PY - 2004/2/14/entrez SP - 1126 EP - 36 JF - The Journal of organic chemistry JO - J Org Chem VL - 69 IS - 4 N2 - The development of efficient methods for the indole synthesis catalyzed by Cu(II) salts and its applications were investigated. Cu(OAc)(2) has been proved to be the best catalyst for the synthesis of various 1-p-tolylsulfonyl or 1-methylsulfonylindoles, which have both electron-withdrawing and electron-donating groups on the aromatic ring and C2 position of indoles. For the primary aniline derivatives, Cu(OCOCF(3))(2) showed good activities, while Cu(OAc)(2) was a good catalyst for the cyclization of secondary anilines. This methodology could be applied to the sequential cyclization reaction for the compounds which have the electrophilic part in the same molecule. By prior treatment with KH, the sequential cyclization was realized to provide the tricyclic ring systems, but it was limited to five- and six-membered rings for the second cyclization. Finally, formal and total synthesis of hippadine with the Cu(II)-promoted indole synthesis as the key step was accomplished. SN - 0022-3263 UR - https://www.unboundmedicine.com/medline/citation/14961661/Development_of_an_efficient_procedure_for_indole_ring_synthesis_from_2_ethynylaniline_derivatives_catalyzed_by_CuII_salts_and_its_application_to_natural_product_synthesis_ DB - PRIME DP - Unbound Medicine ER -