A facile preparation, spectroscopic and chemical properties, crystal structures, and electrochemical behavior of monocarbenium ion compounds stabilized by 3-guaiazulenyl and dihydroxyphenyl (or hydroxymethoxyphenyl) groups

作者：Takekuma Shin ichi^*; Miyamoto Ippei; Hamasaki Akio; Minematsu Toshie

来源：Tetrahedron, 2011, 67(50): 9719-9728.

DOI：10.1016/j.tet.2011.09.148

• Dihydroxybenzaldehydes
• Electrochemical behavior
• Facile preparation
• Guaiazulene
• 3-Guaiazulenylium ion
• Hexafluorophosphoric acid
• Intramolecular hydrogen bond
• Hydroxymethoxybenzaldehydes
• Monocarbenium ions
• NaBH4-reduction
• Protonated benzoquinonemethides
• Spectroscopic properties
• X-ray crystal structures

Reaction of guaiazulene (8) with 2,3-dihydroxybenzaldehyde (9) in methanol in the presence of hexafluorophosphoric acid (i.e., 65% aqueous solution) at 25 degrees C for 2 h gives (3-guaiazulenyl)(2,3-dihydroxyphenyl)methylium hexafluorophosphate (13) in 86% yield. Similarly, reaction of 8 with 2-hydroxy-3-methoxybenzaldehyde (10) [or 3,4-dihydroxybenzaldehyde (11) or 4-hydroxy-3-methoxybenzaldehyde (12)] under the same reaction conditions as for 9 affords the corresponding monocarbenium ion compound 14 (63% yield) [or 15 (43% yield) or 16 (77% yield)], respectively, each product of which is stabilized by 3-guaiazulenyl and dihydroxyphenyl (or hydroxymethoxyphenyl) groups. A facile preparation and crystal structures as well as spectroscopic, chemical, and electrochemical properties of 13-16, possessing two interesting resonance structures, respectively, i.e., a protonated o-(or p-) benzoquinonemethide form and a 3-guaiazulenylium ion form, in a solution of acetonitrile and further, in a single crystal, are reported.

• 出版日期2011-12-16