Asymmetric one-pot sequential Friedel–Crafts-type alkylation and α-oxyamination catalyzed by a peptide and an enzyme

• Kengo Akagawa,
• Ryota Umezawa and
• Kazuaki Kudo

Beilstein J. Org. Chem. 2012, 8, 1333–1337, doi:10.3762/bjoc.8.152

• -functionalized indole or pyrrole derivatives in a highly enantioselective manner. Keywords: Friedel–Crafts-type alkylation; laccase; one-pot reaction; organocatalysis; α-oxyamination; resin-supported peptide catalyst; Findings Indole derivatives represent a class of biologically active compounds [1][2][3], and

• they often have chiral carbon chains attached to indole rings. A Friedel–Crafts-type asymmetric alkylation (FCAA) to indoles is a versatile method for synthesizing such chiral indole derivatives. To date, a number of FCAA reactions by either metal catalysts or organocatalysts have been reported [4][5

• followed by oxygenation at the α-position of the carbonyl group. If such a sequence can be realized in a one-pot reaction, it would be a powerful method for the synthesis of oxy-functionalized indole derivatives with operational simplicity. To date, there has been no report on the FCAA reaction combined

Amines as key building blocks in Pd-assisted multicomponent processes

• Didier Bouyssi,
• Nuno Monteiro and
• Geneviève Balme

Beilstein J. Org. Chem. 2011, 7, 1387–1406, doi:10.3762/bjoc.7.163

• indole derivatives have been reported because they occur in numerous natural products and bioactive compounds. Among these different strategies, those involving a palladium-catalyzed coupling reaction have received much attention [25] and one of the most commonly used procedures involves a one-pot two

• , and the best results were obtained when Pd/C–PPh3 was used as the catalyst system (Scheme 22). Another attractive palladium-mediated multicomponent approach towards the synthesis of indole derivatives involving the cyclization of a 2-alkynylaniline intermediate is based on a sequential, site-selective

• coupling of aryl chlorides. This was followed by an intramolecular alkyne–hydroamination (addition of an N–H bond across a carbon–carbon multiple bond) leading to the corresponding indole derivatives 52. The amination/alkyne–hydroamination sequence requires the addition of 1.5 equiv of t-BuOK to reach

Solvent- and ligand-induced switch of selectivity in gold(I)-catalyzed tandem reactions of 3-propargylindoles

• Estela Álvarez,
• Delia Miguel,
• Patricia García-García,
• Manuel A. Fernández-Rodríguez,
• Félix Rodríguez and
• Roberto Sanz

Beilstein J. Org. Chem. 2011, 7, 786–793, doi:10.3762/bjoc.7.89

• -indole migration in 3-propargylindoles. Results and Discussion It is an intriguing possibility that the aura-Nazarov reaction may also take place with substrates bearing aromatic substituents at both the propargylic and terminal positions, and thus allow access to new functionalized indole derivatives

• almost exclusively to the formation of iso-Nazarov products 3 [13][14]. For instance, indoles 1j and 1k, bearing a methyl and a phenyl group at C-2, respectively, provided the corresponding indole derivatives 3j and 3k with high selectivity when the reaction was conducted in CH2Cl2 with (Ph3P)AuCl/AgSbF6

• favored the Nazarov pathway: Approximately 3/1 ratios of the corresponding indole derivatives 3l, m/4l, m were obtained (Scheme 4) [32]. In addition, we were able to isolate the new Nazarov compounds 4l and 4m, albeit in low yields (Scheme 4). Finally, when the more sterically demanding isopropyl group

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

• . The wide range of alkene substrates and the low catalyst amounts render this method a highly efficient and convenient synthesis of 3-functionalized indole derivatives (Scheme 19). An elegant PtCl2-catalyzed intramolecular alkylation of indoles with inactivated alkenes has been developed by Widenhoefer

An expedient and new synthesis of pyrrolo[1,2-b]pyridazine derivatives

• Rajeshwar Reddy Sagyam,
• Ravinder Buchikonda,
• Jaya Prakash Pitta,
• Himabindu Vurimidi,
• Pratap Reddy Padi and
• Mahesh Reddy Ghanta

Beilstein J. Org. Chem. 2009, 5, No. 66, doi:10.3762/bjoc.5.66

•  1) was synthesized in 21% yield from 1-aminopyrrole and 3-ethoxyacrolein diethylacetal [26]. As a part of our continued interest in the development of new synthetic methods for highly substituted pyrrole and indole derivatives [27][28], we have developed a new synthetic route to pyrrolo[1,2-b

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

• -catalyzed reactions in aqueous media, we have reported an efficient synthesis of 2-substituted indoles via a Pd/C-catalyzed coupling-cyclization process in water [14]. Herein, we report a further continuation of our previous work towards the synthesis of a variety of indole derivatives along with the

• N-substituted indole derivatives successfully we then undertook the synthesis of the target indole C. Compound C was prepared from bromo compound 4 following a 7-step process using the Pd/C-mediated indole synthesis as a key step as shown in Scheme 2. Thus treatment of bromide 4 with Na2SO3 provided

• . Conclusions In conclusion, we have demonstrated the potential of our previously reported palladium on carbon mediated practical synthesis of 2-substituted indoles in water. Besides preparing a wide variety of indole derivatives the methodology was utilized to prepare one of our target indole derivatives

Novel base catalysed rearrangement of sultone oximes to 1,2-benzisoxazole- 3-methane sulfonate derivatives

• Veera Reddy Arava,
• Udaya Bhaskara Rao Siripalli,
• Vaishali Nadkarni and
• Rajendiran Chinnapillai

Beilstein J. Org. Chem. 2007, 3, No. 20, doi:10.1186/1860-5397-3-20

• activities and are useful in different therapies. The 1,2-benzisoxazole moieties are isosteric with indoles and can mimic/bind to biologically important enzymes in a manner similar to indole derivatives. Out of many biologically active compounds, zonisamide is widely prescribed as an anti-epileptic drug. It