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

• . A gold-catalyzed direct alkynylation of indole and pyrrole heterocycles 204 with a benziodoxolone-based hypervalent iodine reagent 203 has been developed [91]. The functional group tolerance was greatly increased when compared with direct alkynylation of indoles reported previously. Kar et al

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

• -pot procedure with the Au(I)-catalyzed C3-selective direct alkynylation of indoles using the benziodoxolone reagent TIPS-EBX to give a mild, easy and straightforward entry to 2-substituted-3-alkynylindoles. The reaction can be applied to unprotected anilines, was tolerant to functional groups and easy

• to carry out (RT, and requires neither an inert atmosphere nor special solvents). Keywords: alkynylation; direct functionalization; gold; hypervalent iodine; indoles; Introduction Indoles are widespread in both natural products and synthetic drugs [1][2] and as a result, their synthesis and

• alkynylation with bromoacetylenes [29]. New methods are needed to expand the scope of this transformation and Au catalysis appears especially promising, due to its broad functional groups tolerance, which could allow the direct use of unprotected anilines. Recently, the direct alkynylation of preformed

C–C (alkynylation) vs C–O (ether) bond formation under Pd/C–Cu catalysis: synthesis and pharmacological evaluation of 4-alkynylthieno[2,3-d]pyrimidines

• Dhilli Rao Gorja,
• K. Shiva Kumar,
• K. Mukkanti and
• Manojit Pal

Beilstein J. Org. Chem. 2011, 7, 338–345, doi:10.3762/bjoc.7.44

• -alkynylthieno[2,3- d]pyrimidines were prepared via alkynylation of 4-chlorothieno[2,3-d]pyrimidines in good to excellent yields. Some of the compounds synthesized were tested for cytotoxic activity in vitro. Keywords: catalysis; C–C bond; copper; palladium; thieno[2,3-d]pyrimidine; Introduction Alkynyl

• halopyrimidines with terminal alkynes [1][2][3] (for a review see [8]). While alkynylation of the thiophene ring of thienopyrimidines under Sonogashira conditions [9] has previously been reported [6], a similar coupling reaction on the pyrimidine ring of thieno[2,3-d]pyrimidines is uncommon in the literature [10

• ]. The use of Pd/C–CuI–PPh3 as a less expensive catalyst system for efficient Sonogashira coupling has been explored earlier. Due to our continuing interest in Pd/C-mediated alkynylation of aryl and heteroaryl halides we decided to investigate the Pd/C-based methodology for the synthesis of our target

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

• review. A related cationic Ru-vinylidene complex was used for an efficient alkynylation of pyridines with (alkyn-1-yl)trimethylsilane [98]. Based on these preliminary results, various catalytic propargylations of arenes have been developed, employing catalysts such as Mo/chloranil [16

Diastereoselective functionalisation of benzo-annulated bicyclic sultams: Application for the synthesis of cis-2,4-diarylpyrrolidines

• Susan Kelleher,
• Pierre-Yves Quesne and
• Paul Evans

Beilstein J. Org. Chem. 2009, 5, No. 69, doi:10.3762/bjoc.5.69

• above proving inefficient, palladium chemistry was subsequently considered. The vinyl bromide 24a was reported to participate in Sonagashira alkynylation chemistry; however, yields of the resultant enyne were low [20]. Therefore, we decided to investigate Suzuki–Miyaura cross-coupling reaction as a

Pd/C-mediated synthesis of α-pyrone fused with a five-membered nitrogen heteroaryl ring: A new route to pyrano[4,3-c]pyrazol-4(1H)-ones

• Dhilli Rao Gorja,
• Venkateswara Rao Batchu,
• Ashok Ettam and
• Manojit Pal

Beilstein J. Org. Chem. 2009, 5, No. 64, doi:10.3762/bjoc.5.64

• Industrial Estate, Bollaram, Jinnaram Mandal, Medak District, Andra Pradesh 502 325, India present address: Institute of Life Sciences, University of Hyderabad Campus, Gachibowli, Hyderabad 500 046, Andhra Pradesh, India 10.3762/bjoc.5.64 Abstract Pd/C-mediated alkynylation of 5-iodo-pyrazole-4-carboxylic

Regioselective alkynylation followed by Suzuki coupling of 2,4-dichloroquinoline: Synthesis of 2-alkynyl- 4-arylquinolines

• Ellanki A. Reddy,
• Aminul Islam,
• K. Mukkanti,
• Venkanna Bandameedi,
• Dipal R. Bhowmik and
• Manojit Pal

Beilstein J. Org. Chem. 2009, 5, No. 32, doi:10.3762/bjoc.5.32

• ) 10.3762/bjoc.5.32 Abstract A two step synthesis of 2-alkynyl-4-arylquinolines has been accomplished via Pd/C-mediated regioselective C-2 alkynylation of 2,4-dichloroquinoline in water followed by Suzuki coupling at C-4 of the resulting 4-chloro derivative. Keywords: alkyne; boronic acid; catalysis; 2,4

• . (a) arylation at C-4 followed by alkynylation at C-2 or (b) alkynylation at C-2 followed by arylation at C-4. Methodologies based on strategy ‘a’ have been reported earlier. For example, Sonogashira coupling of a terminal alkyne with 2-chloro-4-aryl substituted quinoline [3] in the presence of (PPh3

• biological significance we have reported Pd/C-mediated regioselective C-2 alkynylation of 2,4-dichloroquinoline in water [6]. However, only one example of regioselective C-2 alkynylation was reported and no detailed study has been carried out previously. Herein we report the preparation of a series of 2

A short stereoselective synthesis of (+)-(6R,2′S)-cryptocaryalactone via ring- closing metathesis

• Palakodety Radha Krishna,
• Krishnarao Lopinti and
• K. L. N. Reddy

Beilstein J. Org. Chem. 2009, 5, No. 14, doi:10.3762/bjoc.5.14

• short stereoselective synthesis of (+)-(6R,2′S)-cryptocaryalactone was successfully completed. Key steps included the application of Carreira’s asymmetric alkynylation reaction to form a propargylic alcohol and subsequently lactone formation using the powerful ring-closing metathesis reaction. Keywords

• : Carreira asymmetric alkynylation; Cryptocarya bourdilloni GAMB (Lauraceae); ring-closing metathesis; Sharpless asymmetric epoxidation; Introduction Natural products play an important role in the development of drugs and mankind has always taken advantage of nature as pharmacy: approximately 40% of the

• itself could be realised from the acryloylation of the corresponding homoallylic alcohol which in turn can be synthesized from 7. Chiral propargyl alcohol 7 was obtained by the Carreira asymmetric alkynylation reaction of the corresponding aldehyde, which was synthesized from the corresponding primary

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

• constructed with excellent stereoselectivity by asymmetric alkynylation of α-tetrahydrofuranic aldehyde 114 with 1,6-heptadiyne (115). Then Sonogashira coupling of 116 and the iodide 117 followed by hydrogenation and deprotection provided murisolin (111). The spectroscopic data of synthetic 111 (1H NMR, 13C