Versatile and regioselective synthesis of polysubstituted and highly oxygenated phenols via Dötz reaction of α-alkoxyvinyl(ethoxy)carbene complexes with alkynes

Mabel M. Montenegro, José Luis Vega-Báez, Miguel A. Vázquez, Ma Inés Flores-Conde, Arturo Sánchez, Miguel A. González-Tototzin, Rsuini U. Gutiérrez, J. Miguel Lazcano-Seres, Francisco Ayala, L. Gerardo Zepeda, Joaquín Tamariz, Francisco Delgado

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

A comparative study of reactivity and selectivity of α-alkoxyvinyl(ethoxy) Fischer carbene complexes (CO)5M = C[C(=CHR1)(OR)]OCH2CH3 [7a–d: M = Cr; 12a–c: M = Mo; 13a–d: M = W; a: R1 = H, R = CH2CH3; b: R1 = H, R = CH2CH2CH3; c: R1 = H, R = CH2CH2CH2CH3; d: R1 = CH3, R = Et (E and Z)] with terminal and internal alkynes (14a–g) in benzannulation reactions is described. The complexes 7 and 12–13 display a remarkable reactivity toward different alkynes. The [3 + 2+1] cycloaddition or benzannulation reactions between the latter carbene complexes and alkynes 14 were found to be highly regio- and chemoselective only giving those products with the largest substituent of the acetylenic component located at the ortho position to the hydroxyl group, and favoring the formation of new and highly oxygenated and polysubstituted phenols containing only electron-donating groups. The regiochemistry assignment of the cycloadducts was supported by NOE measurements. Phenols 15c, 16e, and 18b were further characterized by single-crystal X-ray diffraction.

Original languageEnglish
Pages (from-to)41-54
Number of pages14
JournalJournal of Organometallic Chemistry
Volume825-826
DOIs
StatePublished - 15 Dec 2016

Keywords

  • (α-Alkoxyvinyl)carbene complexes
  • Dötz benzannulation
  • Regioselective cycloaddition
  • Trioxygenated and polysubstituted phenols

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