Benzo(B)Thiophene → 2-Bromobenzo(b)thiophene

HRID 2121278Notes

Reaction equation

HRID 2121278 reaction equation
Br[C:2]1[C:3]2[CH:10]=[CH:9][CH:8]=[CH:7][C:4]=2[S:5][CH:6]=1.S1C=CC2C=CC=CC1=2.C([Li])CCC.[Br:25]Br>Cl[Ni]1(Cl)[P](C2C=CC=CC=2)(C2C=CC=CC=2)CCC[P]1(C1C=CC=CC=1)C1C=CC=CC=1>[Br:25][C:6]1[S:5][C:4]2[CH:7]=[CH:8][CH:9]=[CH:10][C:3]=2[CH:2]=1

Participants

6

Reactant 4

HCID 7221Benzo(B)Thiophene2×HCID 24408BromineHCID 123250Benzo(b)thiophene, 3-bromo-2×HCID 178418339Butyllithium

Product 1

HCID 947862-Bromobenzo(b)thiophene

Reagents, catalysts & solvents 1

HCID 178418745HCID 178418745, compoundCatalyst

Procedure

Starting from the commercially available 3-bromobenzo[b]thiophene (5), a synthetic route to poly(2,2′-bisbenzo[b]thiophene) (4) is outlined below in Scheme 1. 3-bromobenzo[b]thiophene (5) is alkylated to (6) using an alkyl grignard and Ni(dppp)Cl2. Benzo[b]thiophene (6) is brominated at the 2-position using n-butyllithium followed by bromine to yield (7). 2-Bromobenzo[b]thiophene (7) is homo-coupled using a liganded nickel complex reducing agent (generated from NaH, t-AmONa, Ni(OAc)2 and bipyridine) to yield 2,2′-bisbenzo[b]thiophene (2). Bromination of 2,2′-bisbenzo[b]thiophene (2) with N-bromosuccinimide or bromine water yields 5-5′-dibromo 2,2′-bisbenzo[b]thiophene (8).

Sources & evidence

ORD record
ord-5899f24b50da4c299fcc0b7d8566d165
Source dataset
uspto-grants-2004_02
Patent number
US06695978B2

Reaction notes

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