A review of new developments in the Friedel–Crafts alkylation – From green chemistry to asymmetric catalysis

• Magnus Rueping and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2010, 6, No. 6, doi:10.3762/bjoc.6.6

• efficient Friedel–Crafts alkylations of arenes and heteroarenes using only catalytic amounts of a Lewis acid has gained much attention over the last decade. The new catalytic approaches described in this review are favoured over classical Friedel–Crafts conditions as benzyl-, propargyl- and allyl alcohols

• descriptions of a Lewis acid used in organic synthesis but also the first example of what was later to be called Friedel–Crafts alkylation (FC alkylation) after its inventors. Today Friedel–Crafts alkylations remain the method of choice for the alkylation of arenes and heteroarenes. Over the intervening years

• bearing methyl, methoxy or hydroxy functionalities as well as heteroarenes, including thiophenes or 3-methylindole with a good para/ortho/meta regioselectivity (Scheme 10). In addition, they successfully used benzyl acetates, 1-phenylethanol and β-hydroxy-substituted benzyl alcohols as alkylating reagents

The efficient synthesis of dibenzo[d,d′]benzo[1,2-b:4,3-b′]dithiophene and cyclopenta[1,2-b:4,3-b′]bis(benzo[d]thiophen)-6-one

• Zhihua Wang,
• Sheng Zhu,
• Jianwu Shi and
• Hua Wang

Beilstein J. Org. Chem. 2009, 5, No. 55, doi:10.3762/bjoc.5.55

• [1,2-b:4,3-b′]dithiophene; McMurry reaction; preparation; Introduction With considerable environmental stability and flexibility in synthesis, π-extended heteroarenes containing thiophene rings within an polyaromatic ring system are currently of great interest because they can potentially be used to

• fabricate organic field-effect transistors (OFETs) [1][2][3][4][5][6][7], light emitting diodes (LEDs) [8][9], and photovoltaic cells [10]. Various novel π-extended heteroarenes, e.g. dibenzo[d,d′]thieno[3,2-b:4,5-b′]dithiophene [11], pentathienoacene [12], and benzo[1,2-b:4,5-b′]bis[b]benzothiophene [13

Synthesis of rigidified flavin–guanidinium ion conjugates and investigation of their photocatalytic properties

• Harald Schmaderer,
• Mouchumi Bhuyan and
• Burkhard König

Beilstein J. Org. Chem. 2009, 5, No. 26, doi:10.3762/bjoc.5.26

• flavin heteroarenes are observed. The structure of compound 1 in the solid state (Figure 2) shows an almost identical orientation of the flavin group to that of the acid 6. The acyl guanidinium ion group is almost planar and in a parallel orientation relative to the Kemp’s acid imide group. 2-D NMR

Transition- metal/Lewis acid free synthesis of acyl benzothiophenes via C-C bond forming reaction

• Sarbani Pal,
• Mohammad Ashrafuddin Khan,
• P. Bindu and
• P. K. Dubey

Beilstein J. Org. Chem. 2007, 3, No. 35, doi:10.1186/1860-5397-3-35

• Lewis acid/transition metal free synthesis of acyl benzothiophenes could provide an easy access to a library of benzothiophene based analogues of potential biological interest. Notably, while the use of various arenes/heteroarenes has been explored in the previous study, [25][26][27][28][29][30] the use

m-Iodosylbenzoic acid – a convenient recyclable reagent for highly efficient aromatic iodinations

• Andreas Kirschning,
• Mekhman S. Yusubov,
• Roza Y. Yusubova,
• Ki-Whan Chi and
• Joo Y. Park

Beilstein J. Org. Chem. 2007, 3, No. 19, doi:10.1186/1860-5397-3-19

• Table 2). Addition of aqueous H2SO4 accelerated the iodination of benzenes. For heteroarenes 7j and 7o this additive was not required and if an additional alcohol group was present (see 7n), addition of aqueous H2SO4 resulted in its oxidation. Compared to diacetoxyiodobenzene (DIB) 1a and its polymeric