Regioselective Haloaromatization of 1, 2-Bis (ethynyl) benzene via Halogen Acids and PtCl2. Platinum-Catalyzed 6-π Electrocyclization of 1, 2-Bis (1'-haloethenyl) …

CY Lo, MP Kumar, HK Chang, SF Lush…

Index: Lo, Ching-Yu; Kumar, Manyam Praveen; Chang, Hsu-Kai; Lush, Shie-Fu; Liu, Rai-Shung Journal of Organic Chemistry, 2005 , vol. 70, # 25 p. 10482 - 10487

Full Text: HTML

Citation Number: 29

Abstract

Treatment of 1, 2-bis (ethynyl) benzene (1) with aqueous HX (X= Br, I) in hot 3-pentanone (100-105° C, 2 h) afforded 1, 2-bis (1'-haloethenyl) benzene species 2-Br and 2-I in 98% and 95% yields, respectively. The hydrochlorination of endiyne 1 failed to proceed at elevated temperature but was implemented efficiently by PtCl2 (5 mol%) in hot 3-pentanone (100° C, 2 h) to give 1, 2-bis (1'-chloroethenyl) benzene 2-Cl in 80% yield. In the presence ...