Selective Multiple Magnesiations of the Thieno[3,2‐b]thiophene Scaffold

Abstract

A full functionalization of all four positions of the thieno[3,2-b]thiophene scaffold was achieved. Starting from 2,5-dichlorothieno[3,2-b]thiophene, magnesiation of the 3- and 6-position using tmpMgCl⋅LiCl furnishes, after trapping with various electrophiles, 3,6-difunctionalized dichlorothieno[3,2-b]thiophenes. Subsequent dechlorination and regioselective metalation or regioselective magnesium insertion into the CCl bond provides fully functionalized thieno[3,2-b]thiophenes. Furthermore, new condensed heterocycles and small oligomers of these compounds with potential applications in material chemistry have been prepared.

Hexacyclic lactam building blocks for highly efficient polymer solar cells

“…In order to endow monomers and polymers with good solubility, 2octyldodecyl (OD) or 2-hexyldecyl (HD) as side chains were introduced onto TD1 or TD2, respectively. As shown in Scheme 1, monomer synthesis started from bromination of diethyl thieno [3,2b]thiophene-3,6-dicarboxylate (1) 12 . Compound 2 was hydrolyzed to produce compound 3, which reacted with oxalyl chloride, and then with N-(2-octyldodecyl)thiophen-3-amine or N-(2hexyldecyl)thiophen-3-amine to produce 4a or 4b, respectively.…”

Highly Regioselective Preparation of Heteroaryl–Magnesium Reagents by Using a Br/Mg Exchange

“…We assume that this might be due to the too-long distance between the bromine at position 2 of the thiophene ring and the heteroatom of the MeO or Me 2 N group of the phenyl ring (or the pyridyl or thienyl substituent) caused by the almost perpendicular orientation of the thiophene ring and the substituents at position 3. Because thienothiophenes are important building blocks for the preparation of organic materials, [4] we also performed regioselective functionalisations of this scaffold by using iPrMgCl·LiCl (1 a) ( Table 1, entries 19 and 20).…”

“…The corresponding magnesium species 9 a-d were obtained in satisfactory regioselectivities of up to 28:1 ( Table 3). Subsequent Negishi cross-coupling reactions, after transmetalation with ZnCl 2 , led to the formation of the trisubstituted pyridine derivatives 10 a-d in good yields (60-88 %; Table 3, entries [1][2][3][4]. Both electron-poor and electron-rich aryl iodides were used successfully.…”

Copper‐ and Cobalt‐Catalyzed Syntheses of Thiophene‐Based Tertiary Amines

“…To this purpose, we involved in the amination 2‐thienylzinc chlorides prepared from 2,2′‐bithiophene and thieno[3,2‐ b ]thiophene by deprotomagnesiation using TMPMgCl · LiCl, followed by transmetalation (top). Similarly, we performed the amination of the organozinc chloride coming from 1,3‐dithiole‐2‐thione, generated by using the same base at low temperature followed by transmetalation (bottom).…”