Indole-Derived Arynes and Their Diels−Alder Reactivity with Furans

• Published in: Organic letters Vol. 9; no. 21; pp. 4135 - 4137
• Main Authors: Buszek, Keith R, Luo, Diheng, Kondrashov, Mikhail, Brown, Neil, VanderVelde, David
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 11.10.2007; Amer Chemical Soc
• Subjects: Alkynes - chemistry; Benzene Derivatives - chemistry; Chemistry; Chemistry, Organic; Furans - chemistry; Heterocyclic Compounds, 2-Ring - chemistry; Indoles - chemical synthesis; Indoles - chemistry; Molecular Structure; Physical Sciences; Science & Technology; Stereoisomerism; ALKENES; (+/-)-CIS-TRIKENTRIN-B; TELEOCIDIN; DERIVATIVES; BENZYNE
• ISSN: 1523-7060; 1523-7052
• DOI: 10.1021/ol701595n

Arynes derived from any position of the ubiquitous indole nucleus are unknown. We have now provided the first evidence for the formation and trapping of the 4,5-, 5,6-, and 6,7-indolynes. A series of o-dihalo indoles (Cl, Br, F) were synthesized and reacted under metal-halogen exchange conditions to give Diels−Alder cycloadducts in high yield with furan. The use of an excess of tert-butyllithium resulted in the rearrangement of the initially formed cycloadduct; however, employing only a slight excess of n-butyllithium cleanly gave cycloadducts with furan.