One-pot synthesis of substituted styrenes from vicinal dibromoalkanes and arylboronic acids

Abstract

Dehydrobromination of vicinal dibromoalkanes in systems comprising 1,2 dimethoxy ethane, N butyl N´ methylimidazolium tetrafluoroborate (or tetrabutylammonium bromide), and a base with subsequent palladium catalyzed cross coupling of the thus formed bromoalkenes with arylboronic acids furnished substituted styrenes.

Halogenation of organic compounds in ionic liquids

“…Furthermore, these workers investigated the dehydrobromination of vic-dibromoalkanes in the absence of a hydroxyl functionality (95a-c) to the corresponding bromoalkene isomers (96a-c, Z-97a-c, E-97a-c) in the presence of different bases in various ILs (Scheme 38). 111 Chemoselectivity towards the formation of the product 96 was observed for these substrates. The effect of the following bases was studied: K 2 CO 3 , K 3 PO 4 and KOH.…”

“…In addition to the main vinylic bromide product 89 (94%), a minor cyclized product (90) was also formed (6%) (Scheme 37). 110 In continuation, some other 1,2-dibromoalkanes (91) bearing a hydroxyl group at the 4-position were investigated, by applying 4 equiv of K 2 CO 3 in [bmim] [BF 4 ] at 20 C for 1-4 h. 111 The reaction gave a mixture of isomers 92, Z-93 and E-93, together with the cyclized 3-bromotetrahydrofuran derivative 94 with high selectivity for either the E-93 isomer or the cyclized product (94) ( Table 17, entries 1-3). Furthermore, these workers investigated the dehydrobromination of vic-dibromoalkanes in the absence of a hydroxyl functionality (95a-c) to the corresponding bromoalkene isomers (96a-c, Z-97a-c, E-97a-c) in the presence of different bases in various ILs (Scheme 38).…”

Industrial Riboflavin Fermentation Broths Represent a Diverse Source of Natural Saturated and Unsaturated Lactones

“…γ-( E )-Dec-5-enlactone was synthesized according to the method of Miyakoshi and Tsukasa . ( E )-1-Bromohex-1-ene was synthesized according to Tarchini et al and Tikhonov et al The reaction mixture was subsequently purified and analyzed as described above.…”