Enantioselective synthesis of planar chiral ferrocenes via palladium-catalyzed annulation with diarylethynes

• Yan-Chao Shi,
• Rong-Fei Yang,
• De-Wei Gao and
• Shu-Li You

Beilstein J. Org. Chem. 2013, 9, 1891–1896, doi:10.3762/bjoc.9.222

• [51][52][53][54][55][56][57]. The product could be transformed into a planar chiral P,N-ligand, which was found to be efficient for Pd-catalyzed allylic alkylation reaction albeit with low enantioselectivity. We envisaged that by introducing a larger substituent R in the ferrocene Cp ring would

• ). The allylic substitution reactions of (rac)-4 had been carried out. The allylic alkylation reaction proceeded in 95% yield and 44% ee (Scheme 3, reaction 1) and the allylic amination reaction proceeded in 32% yield and 43% ee (Scheme 3, reaction 2) [69][70][71]. Although only moderate

• enantioselectivity was obtained, significant increase of enantioselectivity was obtained comparing with 15% ee obtained by (Sp)-L2 in allylic alkylation reaction [51]. The results indicated that the planar P,N-ligand with a larger R group could improve the enantioselectivity. Conclusion In summary, we reported a

Asymmetric allylic alkylation of Morita–Baylis–Hillman carbonates with α-fluoro-β-keto esters

• Lin Yan,
• Zhiqiang Han,
• Bo Zhu,
• Caiyun Yang,
• Choon-Hong Tan and
• Zhiyong Jiang

Beilstein J. Org. Chem. 2013, 9, 1853–1857, doi:10.3762/bjoc.9.216

• and Biological Chemistry, Nanyang Technological University, 21 Nanyang Link, Singapore 637371 10.3762/bjoc.9.216 Abstract In the presence of a commercially available Cinchona alkaloid as catalyst, the asymmetric allylic alkylation of Morita–Baylis–Hillman carbonates, with α-fluoro-β-keto esters as

• ). Keywords: allylic alkylation; asymmetric catalysis; fluorine; fluoro-β-keto esters; Morita–Baylis–Hillman carbonates; natural product; Introduction Fluorine is the most electronegative element in the periodic table, resulting in a highly polar C–F bond. This gives fluoro-organic compounds unique

• conjugate addition and Mannich reaction of α-fluoro-β-ketoesters with excellent results [38][39][40]. Herein, we wish to report the first allylic alkylation of MBH carbonates with α-fluoro-β-ketoesters in excellent enantioselectivities and moderate diastereoselectivities, furnishing enantiopure fluorinated

Inter- and intramolecular enantioselective carbolithiation reactions

• Asier Gómez-SanJuan,
• Nuria Sotomayor and
• Esther Lete

Beilstein J. Org. Chem. 2013, 9, 313–322, doi:10.3762/bjoc.9.36

• . In this case, the use of a copper-base chiral catalytic system allows carbon–carbon bond formation by allylic alkylation with alkyllithiums, with high enantioselectivities and high functional-group tolerance [28][29]. This process may open new interesting applications in organolithium chemistry

Palladium-catalyzed dual C–H or N–H functionalization of unfunctionalized indole derivatives with alkenes and arenes

• Gianluigi Broggini,
• Egle M. Beccalli,
• Andrea Fasana and
• Silvia Gazzola

Beilstein J. Org. Chem. 2012, 8, 1730–1746, doi:10.3762/bjoc.8.198

• and tetrahydro-γ-carbolines was performed starting from 2- and 3-alkenylindoles by Pd-catalyzed asymmetric allylic alkylation. A series of (E)-5-substituted indolylcarbonates 33, easily available from the 2-indolylcarbaldehyde, undergo cyclization through a π-allyl-palladium complex by treatment with

Organocatalytic asymmetric allylic amination of Morita–Baylis–Hillman carbonates of isatins

• Hang Zhang,
• Shan-Jun Zhang,
• Qing-Qing Zhou,
• Lin Dong and
• Ying-Chun Chen

Beilstein J. Org. Chem. 2012, 8, 1241–1245, doi:10.3762/bjoc.8.139

• the other hand, the asymmetric addition to electrophilic imines of isatins is also an attractive pathway, and a variety of examples have been presented [16][17][18][19][20][21]. Recently, we have developed the asymmetric allylic alkylation reactions [22] with Morita–Baylis–Hillman (MBH) carbonates of

A straightforward approach towards combined α-amino and α-hydroxy acids based on Passerini reactions

• Ameer F. Zahoor,
• Sarah Thies and
• Uli Kazmaier

Beilstein J. Org. Chem. 2011, 7, 1299–1303, doi:10.3762/bjoc.7.151

• by chelated enolate Claisen rearrangement [22][23] or transition metal-catalyzed allylic alkylation of chelated enolates [24] and subsequent oxidative cleavage of the γ–δ-unsaturated amino acids obtained. Results and Discussion An alternative approach is based on regioselective ring opening of

Gold(I)-catalyzed synthesis of γ-vinylbutyrolactones by intramolecular oxaallylic alkylation with alcohols

• Michel Chiarucci,
• Mirko Locritani,
• Gianpiero Cera and
• Marco Bandini

Beilstein J. Org. Chem. 2011, 7, 1198–1204, doi:10.3762/bjoc.7.139

• environmental sustainable reaction partners for allylic alkylation reactions in the presence of C- as well as X-based (X: heteroatom) nucleophiles [1][2]. Despite their undoubted synthetic/economic advantages (i.e., water is the only stoichiometric byproduct produced), the intrinsic lower reactivity of allylic

• vinylbutyrolactones [18][19][20][21][22] as minor products in the Friedel–Crafts-type allylic alkylation of arenes [23]. The wide impact of functionalized γ-lactones on the synthesis of naturally occurring compounds [24][25][26] prompted us to optimize a direct synthesis of vinylbutyrolactones by direct gold

• confirms the allylic SN1 mechanism for the present methodology [44]. The high chemoselectivity guaranteed by the gold catalysts is worthy of note, as it channels the reaction toward the allylic alkylation mechanism without any contamination deriving from transesterification reactions. This evidence is

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

Total synthesis of (±)-coerulescine and (±)-horsfiline

• Mukund G. Kulkarni,
• Attrimuni P. Dhondge,
• Sanjay W. Chavhan,
• Ajit S. Borhade,
• Yunnus B. Shaikh,
• Deekshaputra R. Birhade,
• Mayur P. Desai and
• Nagorao R. Dhatrak

Beilstein J. Org. Chem. 2010, 6, 876–879, doi:10.3762/bjoc.6.103

• radical cyclizations [20][21][22][23][24], electrophilic cyclization [25], asymmetric nitroolefination reaction [26], palladium asymmetric allylic alkylation [27], palladium-catalyzed domino Heck–cyanation [28], Pd-catalyzed intramolecular cyanoamidation [29][30], NHC-mediated O- to C-carboxyl transfer

Understanding the mechanism of Pd-catalyzed allylic substitution of the cyclic difluorinated carbonates

• Jun Xu,
• Xiao-Long Qiu and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2008, 4, No. 18, doi:10.3762/bjoc.4.18

• nucleobases 3-benzoyluracil and 3-benzoylthymine in the presence of a catalytic amount of Pd(PPh3)4 at 60 °C in THF (Scheme 1) [11]. The exclusive regioselectivities of Pd-catalyzed allylic alkylation (Pd-AA) reactions were very interesting. Although Konno et al. have reported that the electron-withdrawing

• fluoroalkyl groups would alter the regioselectivities of acyclic allylic alkylation compared with their non-fluorinated counterparts [12][13][14][15][16][17], their reactions mostly concerned the Pd-catalyzed regio- and stereoselective formate reduction of fluorine-containing allylic mesylates. To the best of

A superior P-H phosphonite: Asymmetric allylic substitutions with fenchol- based palladium catalysts

• Bernd Goldfuss,
• Thomas Löschmann,
• Tina Kop-Weiershausen,
• Jörg Neudörfl and
• Frank Rominger

Beilstein J. Org. Chem. 2006, 2, No. 7, doi:10.1186/1860-5397-2-7

• enantioselectivitites. Allylic alkylation of 1-phenyl-2-propenyl acetate by sodium dimethylmalonate (BSA-method) with Pd-FENOP- or Pd-BIFOP- catalysts. FENOP- and BIFOP-Pd-catalysts in enantioselective allylic substitutions of phenylallyacetate by dimethylmalonate.a) Supporting Information Supporting Information File