Combined directed ortho-zincation and palladium-catalyzed strategies: Synthesis of 4,n-dimethoxy-substituted benzo[b]furans

• Verónica Guilarte,
• M. Pilar Castroviejo,
• Estela Álvarez and
• Roberto Sanz

Beilstein J. Org. Chem. 2011, 7, 1255–1260, doi:10.3762/bjoc.7.146

• benzo[b]furan derivatives has been developed from 3-halo-2-iodoanisoles bearing an additional methoxy group, which have been accessed through an ortho-zincation/iodination reaction. Two palladium-catalyzed processes, namely a Sonogashira coupling followed by a tandem hydroxylation/cyclization sequence

Meta-metallation of N,N-dimethylaniline: Contrasting direct sodium-mediated zincation with indirect sodiation-dialkylzinc co-complexation

• David R. Armstrong,
• Liam Balloch,
• Eva Hevia,
• Alan R. Kennedy,
• Robert E. Mulvey,
• Charles T. O'Hara and
• Stuart D. Robertson

Beilstein J. Org. Chem. 2011, 7, 1234–1248, doi:10.3762/bjoc.7.144

• of N,N-dimethylaniline by the mixed-metal zincate reagent 1 ((TMEDA)Na(TMP)(t-Bu)Zn(t-Bu)) surprisingly led to meta-metallation (zincation) of the aniline, as manifested in the crystalline complex 2 ((TMEDA)Na(TMP)(m-C6H4-NMe2)Zn(t-Bu)), and that iodination of these isolated crystals produced the

• mixture that afforded 4 and 5. This gave the crystalline product 6 ((TMEDA)Na(TMP)(o-C6H4-NMe2)Zn(t-Bu)), the ortho-isomer of the meta-complex 2, as determined from X-ray crystallographic and NMR data. Monitoring the regioselectivity of the reaction by iodination revealed a 16.6:1.6:1.0 ortho:meta:para

• spectroscopic experiments revealed quantitative iodination and the formation of N,N-dimethyl-3-iodoaniline. Now we are looking to paint the complete picture of this surprising synergic meta-deprotonation of N,N-dimethylaniline. The direct meta-zincation reaction: a closer look. Revisiting the reaction, sodium

A practical microreactor for electrochemistry in flow

• Kevin Watts,
• William Gattrell and
• Thomas Wirth

Beilstein J. Org. Chem. 2011, 7, 1108–1114, doi:10.3762/bjoc.7.127

• the flow system [11]. Yoshida et al. also reported the electrochemical iodination of aromatic compounds by elemental iodine followed by a subsequent reaction with aromatic compounds. This sequential method has one main advantage over the batch method, in that the polyiodination problem for highly

• reactive aromatic compounds, based on disguised chemical selectivity, can be avoided by the micromixing of a solution of preformed iodine cations (I+) and a solution of an aromatic compound, increasing the yield of mono iodination product from 38% to 85% [12]. Nishiyama et al. reported the synthesis of

Triazole–Au(I) complex as chemoselective catalyst in promoting propargyl ester rearrangements

• Dawei Wang,
• Yanwei Zhang,
• Rong Cai and
• Xiaodong Shi

Beilstein J. Org. Chem. 2011, 7, 1014–1020, doi:10.3762/bjoc.7.115

• -iodoenone from propargyl esters (Scheme 4a) [43]. As indicated in Scheme 4a, the typical [L–Au]+ catalyst promoted the sequential rearrangement and iodination, giving the thermally, dynamically stable (Z)-isomer [44][45][46]. The cationic TA–Au catalyst, on the other hand, produced the kinetically favored

• (E)-isomer. Notably, treating the allene ester 2a with NIS gave the (E)-isomer as the dominant product. These results imply that the allene iodination should favor the formation of the (E)-isomer (Scheme 4b). The typical [L–Au]+ catalyst not only promoted the propargyl ester 3,3-rearrangement, but

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• compatible with electrophilic fluorinating reagents. Furthermore, it is possible to couple the 6-endo-dig cyclization with iodination and bromination of the presumed vinyl–gold intermediate. However, attempted alkoxychlorination with N-chlorosuccinimide failed. Intermolecular hydroalkoxylation of non

When gold can do what iodine cannot do: A critical comparison

• Sara Hummel and
• Stefan F. Kirsch

Beilstein J. Org. Chem. 2011, 7, 847–859, doi:10.3762/bjoc.7.97

• ]. Interestingly, the bis(pyridine)iodonium tetrafluoroborate reagent [73] (IPy2BF4) developed by Barluenga proved to be the best reagent for the iodination pathway. Diversity-creating transformations In contrast to the examples discussed above, the heterocyclization onto activated alkynes can generate quite

Synthesis, reactivity and biological activity of 5-alkoxymethyluracil analogues

• Lucie Brulikova and
• Jan Hlavac

Beilstein J. Org. Chem. 2011, 7, 678–698, doi:10.3762/bjoc.7.80

• hydrolysis and decarboxylation. Iodination of 5-vinyl analogues 9, 23 and 24 with iodine in the presence of the iodic acid as an oxidizing agent afforded 5-(1-hydroxy-2-iodoethyl)-2'-deoxyuridine (25, 59%), 5-(1-hydroxy-2-iodoethyl)-2'-fluoro-2'-deoxyuridine (26, 72%) and 5-(1-hydroxy-2-iodoethyl)uridine (27

• localization agents, Iwashina and co-workers investigated the radiolabelled 5-(1-methoxy-2-iodoethyl) nucleoside 31 (Figure 4) [15] which was obtained by radio-iodination of 5-(1-methoxy-2-iodoethyl)-2'-deoxyuridine (28) via isotope exchange by the pivalic acid melt method. In addition to the above mentioned 5

One-pot gold-catalyzed synthesis of 3-silylethynyl indoles from unprotected o-alkynylanilines

• Jonathan P. Brand,
• Clara Chevalley and
• Jérôme Waser

Beilstein J. Org. Chem. 2011, 7, 565–569, doi:10.3762/bjoc.7.65

• -alkynylanilines can be followed by 1,4-addition to enones [15][16], iodination [17] or reaction with 1,3-dicarbonyl compounds [18]. Perumal recently demonstrated that aldehydes and nitroalkenes can be used as electrophilic partners [19][20]. Triple bonds can also serve as a second electrophile for the

An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals

• Marcus Baumann,
• Ian R. Baxendale,
• Steven V. Ley and
• Nikzad Nikbin

Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57

Structure and reactivity in neutral organic electron donors derived from 4-dimethylaminopyridine

• Jean Garnier,
• Alan R. Kennedy,
• Leonard E. A. Berlouis,
• Andrew T. Turner and
• John A. Murphy

Beilstein J. Org. Chem. 2010, 6, No. 73, doi:10.3762/bjoc.6.73

• the same potential and was within 10mV of 17′. The reactivity of these two donors was also investigated with substrate 27. Here, 23 and 24 were prepared in situ from 25′ and 26. This afforded the reductive de-iodination product 28 in good yield (84% when using 25′, and 68% when using 26). These

Polar tagging in the synthesis of monodisperse oligo(p-phenyleneethynylene)s and an update on the synthesis of oligoPPEs

• Dhananjaya Sahoo,
• Susanne Thiele,
• Miriam Schulte,
• Navid Ramezanian and
• Adelheid Godt

Beilstein J. Org. Chem. 2010, 6, No. 57, doi:10.3762/bjoc.6.57

• the conversion of hexamer 1b6 and heptamer 1b7 into the alkynes 26 (98% isolated yield) and 27 (90% isolated yield), respectively. Iodination of 1,4-dihexylbenzene The preparation of 1,4-dihexyl-2,5-diiodobenzene (10a) by the iodination of 1,4-dihexylbenzene with a mixture of iodine and potassium

• iodate in HOAc, H2SO4, and water at 70 °C [32][77][78] gave variable yields and on occasions failed. We obtained 10a much more reliably via iodination with iodine and periodic acid in HOAc, H2SO4, water, and dichloromethane at 70 °C [79][80]. Dichloromethane probably acts as a phase compatibiliser

• occasionally detected side reaction. The depicted alkene configuration was chosen assuming a carbometalation process and thus a syn addition of the alkyne onto the hydroxypropyne moiety. Iodination of 1,4-dihexylbenzene. Different routes to compound 14, a representative of the large group of functionalized

A perfluorocyclopentene based diarylethene bearing two terpyridine moieties – synthesis, photochemical properties and influence of transition metal ions

• Falk Wehmeier and
• Jochen Mattay

Beilstein J. Org. Chem. 2010, 6, No. 53, doi:10.3762/bjoc.6.53

• diarylethene unit (3) can be obtained by lithiation of 3-bromo-2-methylbenzo[b]thiophene (1) followed by quenching with perfluorocyclopentene (2), according to the method described by Irie [12]. Electrophilic iodination leads to the diiodo photoswitch 4 (Scheme 1) [13][14]. We decided to use the diiodo switch

Synthesis and binding studies of two new macrocyclic receptors for the stereoselective recognition of dipeptides

• Ana Maria Castilla,
• M. Morgan Conn and
• Pablo Ballester

Beilstein J. Org. Chem. 2010, 6, No. 5, doi:10.3762/bjoc.6.5

• 3 is needed. The starting material for both synthetic routes is 4-iodo-L-phenylalanine (6). We prepared 6 in multigram scale starting from commercial L-phenylalanine (7) by following a described procedure [24] consisting in the iodination of 7 in acetic acid solution in the presence of I2, NaIO3

Ring strain and total syntheses of modified macrocycles of the isoplagiochin type

• Andreas Speicher,
• Timo Backes,
• Kerstin Hesidens and
• Jürgen Kolz

Beilstein J. Org. Chem. 2009, 5, No. 71, doi:10.3762/bjoc.5.71

• and 26 were prepared as the “d” ring for Suzuki coupling with the bromoarene 16 (Scheme 5). First, iodination of 3-hydroxybenzoic acid (18) followed by double methylation and saponification of the methyl ester yielded 4-iodo-3-methoxybenzoic acid (19) which could be reduced in two steps [27] to the

Pd/C- Mediated synthesis of indoles in water

• Mohosin Layek,
• Udaya Lakshmi,
• Dipak Kalita,
• Deepak K. Barange,
• Aminul Islam,
• K. Mukkanti and
• Manojit Pal

Beilstein J. Org. Chem. 2009, 5, No. 46, doi:10.3762/bjoc.5.46

• 8. Iodination of 8 using elemental iodine provided the o-iodoaniline derivative 9 which was converted to the corresponding methanesulfonamide 10. Compound 10 when reacted with phenylacetylene in the presence of 10% Pd/C-CuI-PPh3 and 2-aminoethanol in water provided the desired indole derivative C

Controlling hazardous chemicals in microreactors: Synthesis with iodine azide

• Johan C. Brandt and
• Thomas Wirth

Beilstein J. Org. Chem. 2009, 5, No. 30, doi:10.3762/bjoc.5.30

• regioselectivity following an ionic mechanism. This azido-iodination reaction is by far the most common synthetic application of iodine azide [6][7][8][9][10][11][12][13][14]. Due to the weakness of the iodine–nitrogen bond iodine azide also reacts in a radical manner upon heating, where this weak bond can be

Recent progress on the total synthesis of acetogenins from Annonaceae

• Nianguang Li,
• Zhihao Shi,
• Yuping Tang,
• Jianwei Chen and
• Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

• of 67 to 1,3-dimesitylimidazol-2-ylidene ruthenium benzylidene catalyst (RuCl2(=C(H)-Ph)(PCy3)(IMes)) after protection of the free hydroxyl group afforded the RCM product 68. Hydrogenation of the double bond of dihydrofuran 68 and iodination of the primary alcohol gave 69, which was then utilized to

Synthesis of deep- cavity fluorous calix[4]arenes as molecular recognition scaffolds

• Maksim Osipov,
• Qianli Chu,
• Steven J. Geib,
• Dennis P. Curran and
• Stephen G. Weber

Beilstein J. Org. Chem. 2008, 4, No. 36, doi:10.3762/bjoc.4.36

• . Correspondingly, 3b was treated with silver trifluoroacetate [32] in the presence of iodine providing iodide 5 in 72% yield on a 1 mmol scale (Scheme 2). Results for the iodination were scale dependent; near quantitative yields could be obtained on 0.1 mmol scale preparations, while 1 mmol scale preparations

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

• organometallic compounds, [4][5][6][7][8] and for the synthesis of polyvalent iodine organic compounds. [9][10] In addition, polyvalent organoiodine compounds have served as cooxidants in the iodination of arenes. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35

• ][36] Typical polyvalent iodine sources for these iodination reactions are reagents 1–4 (Figure 1). Iodosylbenzene 5 is not suitable for iodinations because of its low activity. [37] In this report we describe a practical improvement for these iodinations as far as purification of the products and

• oxidation of alcohols to aldehydes and ketones. [42] In the present work we demonstrate the utility of m-iodosylbenzoic acid 6 as a recyclable reagent for the iodination of arenes. In fact reagent 6 can be regarded as a tagged version of iodoso benzene 5 which, if used in access, can be conveniently removed