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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Stereoselective Oxa-Michael Addition of Tyrosine to Propargyl Aldehyde/Esters: Formation of Benzofurans and Flavones

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Vasconcelos, Stanley N. S. [1] ; de Oliveira, Isadora Maria [2] ; Shamim, Anwar [2] ; Zukerman-Schpector, Julio [3] ; Pimenta, Daniel C. [4] ; Stefani, Helio A. [1, 2]
Total Authors: 6
[1] Univ Sao Paulo, Fac Ciencias Farmaceut, Dept Farm, Sao Paulo, SP - Brazil
[2] Univ Sao Paulo, Inst Quim, Dept Quim Fundamental, Sao Paulo, SP - Brazil
[3] Univ Fed Sao Carlos, Dept Quim, Sao Carlos, SP - Brazil
[4] Inst Butantan, Sao Paulo, SP - Brazil
Total Affiliations: 4
Document type: Journal article
Source: ADVANCED SYNTHESIS & CATALYSIS; v. 361, n. 18 JULY 2019.
Web of Science Citations: 0

The steroselective oxa-Michael addition of the phenol moiety present in tyrosine and 3-iodotyrosine to different propargyl aldehydes delivered products with predominantly Z stereochemistry, as evidenced by X-ray crystallography analysis. When ethyl propiolate was used as the propargyl ester source, the products were achieved with exclusively E stereochemistry with yields ranging from 17% to 91%. The oxa-Michael addition compounds served as substrates in the synthesis of 5- and 6-membered heterocyclic compounds. The atmosphere applied to the reaction medium directly influenced the formation of the products. When an inert atmosphere of nitrogen was applied, a 2-aryl-3-formyl-5-alanylbenzofuran core was selectively obtained via a Heck intramolecular reaction, while the reactions carried out under a carbon monoxide atmosphere led exclusively to 6-alanyl-2-arylflavone derivatives via reductive intramolecular acylation. (AU)

FAPESP's process: 16/04289-3 - Synthesis of calcogeno amino acids derivatives and 4-calcogeno quinolines via multicomponent reactions
Grantee:Isadora Maria de Oliveira
Support type: Scholarships in Brazil - Doctorate (Direct)
FAPESP's process: 13/17960-7 - Functionalization of 3-iodo-(L)-Tyrosine via Suzuki-Miyaura reaction using potassium organotrifluoroborate salts
Grantee:Stanley Nunes Siqueira Vasconcelos
Support type: Scholarships in Brazil - Doctorate