e.g. Filippa Pettersson or Cancer Res. 75(6) , 1102-12, (2015) or 10.1002/anie.201600521

Tetrahedron

Iridium-catalyzed borylation of thiophenes: versatile, synthetic elaboration founded on selective C–H functionalization

GA Chotana, VA Kallepalli, RE Maleczka, MR Smith

Index: Chotana, Ghayoor A.; Kallepalli, Venkata A.; Maleczka Jr., Robert E.; Smith III, Milton R. Tetrahedron, 2008 , vol. 64, # 26 p. 6103 - 6114

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Citation Number: 45

Abstract

Iridium-catalyzed borylation has been applied to various substituted thiophenes to synthesize poly-functionalized thiophenes in good to excellent yields. Apart from common functionalities compatible with iridium-catalyzed borylations, additional functional group tolerance to acyl (COMe) and trimethylsilyl (TMS) groups was also observed. High regioselectivities were observed in borylation of 3-and 2, 5-di-substituted thiophenes. ...

3-Chlorothiophene Structure

3-Chlorothiophene

Pinacolborane Structure

~%

2-(4-Chlorothiophen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane Structure

2-(4-Chlorothio...

3-Chlorothiophene-2-boronic acid pinacol ester Structure

3-Chlorothiophe...

2-Iodothiophene Structure

2-Iodothiophene

Pinacolborane Structure

~92%

2-(5-iodothiophen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane Structure

2-(5-iodothioph...

2,5-Dibromothiophene Structure

2,5-Dibromothiophene

Pinacolborane Structure

~55%

2-(2,5-Dibromothiophen-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane Structure

2-(2,5-Dibromot...

2-Acetylthiophene Structure

2-Acetylthiophene

Pinacolborane Structure

~85%

5-Acetylthiophene-2-boronic acid pinacol ester Structure

5-Acetylthiophe...

3-Bromo-2-chlorothiophene Structure

3-Bromo-2-chlor...

Pinacolborane Structure

~78%

2-(4-Bromo-5-chlorothiophen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane Structure

2-(4-Bromo-5-ch...

3-bromo-2,5-dichlorothiophene Structure

3-bromo-2,5-dic...

Pinacolborane Structure

~71%

2-(4-Bromo-5-chlorothiophen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane Structure

2-(4-Bromo-5-ch...

2,5-Dimethylthiophene Structure

2,5-Dimethylthi...

Pinacolborane Structure

~99%

2-(2,5-dimethylthiophen-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane Structure

2-(2,5-dimethyl...

2-(Carbomethoxy)thiophene Structure

2-(Carbomethoxy...

Pinacolborane Structure

~94%

METHYL 5-(4,4,5-TRIMETHYL-[1,3,2]DIOXABOROLAN-2-YL)THIOPHENE-2-CARBOXYLATE Structure

METHYL 5-(4,4,5...

3-Bromothiophene Structure

3-Bromothiophene

Pinacolborane Structure

~%

4-Bromothiophene-2-boronic acid pinacol ester Structure

4-Bromothiophen...

2-(3-bromothiophen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane Structure

2-(3-bromothiop...

2-(2,5-dimethylthiophen-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane Structure

2-(2,5-dimethyl...

~82%

2-(4-bromo-2,5-dimethylthiophen-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane Structure

2-(4-bromo-2,5-...

3-Chlorothiophene Structure

3-Chlorothiophene

Pinacolborane Structure

~%

2-(4-Chlorothiophen-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane Structure

2-(4-Chlorothio...

3-Chlorothiophene-2-boronic acid pinacol ester Structure

3-Chlorothiophe...