Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Transition-metal-catalyzed domino reactions of strained bicyclic alkenes

• Austin Pounder,
• Eric Neufeld,
• Peter Myler and
• William Tam

Beilstein J. Org. Chem. 2023, 19, 487–540, doi:10.3762/bjoc.19.38

• investigated the Ru-catalyzed ring-opening/lactamization of azabenzonorbornadiene derivatives 30 with arylamides 116 (Scheme 21) [64]. Weinreb amides outperformed other arylamides, likely serving as a better directing group for the initial aryl-C–H activation. While the scope of functionalized aryl Weinreb

• amides was quite wide, including different EWGs and EDGs, as well as heterocycles, ortho-substitution was not tolerated. The authors applied the methodology for the synthesis of biologically important benzo[c]phenanthridine derivatives 117. Through methylation and subsequent aromatization of the

Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine

• Dimas J. P. Lima,
• Antonio E. G. Santana,
• Michael A. Birkett and
• Ricardo S. Porto

Beilstein J. Org. Chem. 2021, 17, 28–41, doi:10.3762/bjoc.17.4

• -sulfinimes (+)-95 and (+)-96 were added to a −78 °C solution of the N-methoxy-N-methylacetamide enolate 102, leading to Weinreb amides (+)-97 and (+)-98, respectively, with good yields and high diastereoisomeric excesses (Scheme 11). The reaction of (+)-97 and (+)-98 with five equivalents of methylmagnesium

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

• aromatic coupling partner, including frequently used Weinreb amides or functionalized secondary and primary amides. Regarding the scope of olefin substrates, the reaction tolerated numerous functional groups including acrylates, vinyl silanes or sulfones which was interesting from the post

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

• Stephanie G. E. Amos,
• Marion Garreau,
• Luca Buzzetti and
• Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

• between the aryl substrates 30.1 and the amides 30.2 for the synthesis of the Weinreb amides 30.3 using DCA (OD5) as an organic dye. Under visible-light irradiation, the SET oxidation of 30.2 by the excited state of DCA, followed by a deprotonation, afforded the amidyl radical. This radical behaved as a

Copper-catalyzed enantioselective conjugate addition of organometallic reagents to challenging Michael acceptors

• Delphine Pichon,
• Jennifer Morvan,
• Christophe Crévisy and
• Marc Mauduit

Beilstein J. Org. Chem. 2020, 16, 212–232, doi:10.3762/bjoc.16.24

• , the acylimidazole moiety constituted a privileged surrogate of esters, amides, ketones, and aldehydes. Indeed, this peculiar function, which was readily accessible from the corresponding aldehydes or Weinreb amides, could be efficiently converted into a wide range of carbonyl derivatives, as depicted

• β-alkylated N-acyloxazolidinones could be converted to various derivatives (aldehydes, ketones, Weinreb amides, or carboxylic acids) in good yields and without alteration of the ee values. In 2006, aminohydroxyphosphine L15b was used as a new designer ligand by Nakamura and co-workers for the

Reusable and highly enantioselective water-soluble Ru(II)-Amm-Pheox catalyst for intramolecular cyclopropanation of diazo compounds

• Hamada S. A. Mandour,
• Yoko Nakagawa,
• Masaya Tone,
• Hayato Inoue,
• Nansalmaa Otog,
• Ikuhide Fujisawa,
• Soda Chanthamath and
• Seiji Iwasa

Beilstein J. Org. Chem. 2019, 15, 357–363, doi:10.3762/bjoc.15.31

• ). These results encouraged us to explore the asymmetric intramolecular cyclopropanation of diazo Weinreb amides in a biphasic medium. Asymmetric cyclopropanation using diazo Weinreb amide with Ru(II)-Amm-Pheox Ru(II)-Pheox (cat. 1) was slightly soluble in water, and afforded only a 53% yield of product in

β-Amino functionalization of cinnamic Weinreb amides in ionic liquid

• Yi-Ning Wang,
• Guo-Xiang Sun and
• Gang Qi

Beilstein J. Org. Chem. 2016, 12, 2372–2377, doi:10.3762/bjoc.12.231

• Yi-Ning Wang Guo-Xiang Sun Gang Qi School of Chemistry & Chemical Engineering, Yancheng Institute of Technology, Yancheng, Jiangsu 224051, China 10.3762/bjoc.12.231 Abstract 2-Ns-Protected β-amino Weinreb amides were synthesized by aminochlorination of α,β-unsaturated Weinreb amides in an ionic

• ; ionic liquid; Weinreb amides; Introduction Unlike N-protected α-amino carbonyl compounds, their analogues, the β-amino carbonyl compounds, have drawn relatively little attention. However, the β-amino carbonyl moieties are not only found in natural products [1][2][3], e.g., in the side chain of Taxol

• -Methoxy-N-methylamides, known as Weinreb amides, were first reported by Nahm and Weinreb in 1981 [13]. Since then, the Weinreb amides were found to be useful precursors for the synthesis of their carbonyl equivalents in organic chemistry [14]. By treating with various nucleophiles, such as hydrides

Catalytic asymmetric formal synthesis of beraprost

• Yusuke Kobayashi,
• Ryuta Kuramoto and
• Yoshiji Takemoto

Beilstein J. Org. Chem. 2015, 11, 2654–2660, doi:10.3762/bjoc.11.285

• ) at the ortho position was methyl, or via coupling reactions with C4 units when X was a bromo substituent. The cis-fused tricyclic core of 3 was assumed to be constructed by a stereoselective C–H insertion of diazoester 4, which can be readily prepared from the Weinreb amides 5 or 6 via Claisen

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

• Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

• previously referenced examples, (S)-Binap has also been used in the 1,4-addition of aryltrialkoxysilanes to a series of α,β-unsaturated amides [154]. In 2005, Hayashi and co-workers developed conditions for the 1,4-arylation of various Weinreb amides, which utilized (S,S)-75 as the chiral ligand [130]. Xu

• ) iodide was added to retard this reaction by modifying the reduction potential of SmI2 [173][174]. The authors were pleased that the cyclization of Weinreb amides 81 and 83 proceeded in high yields and diasteroselectivities. As the authors used 5 equiv SmI2 in their reaction and it is well documented that

• diastereoselectivities. Starting in 2005, Shibasaki and co-workers reported both the gadolinium and strontium-catalyzed asymmetric 1,4-cyanation of α,β-unsaturated N-acylpyrroles [205][206][207]. N-Acylpyrroles have proven to be useful alternatives to Weinreb amides, because they share many of the same advantages but N

Concise, stereodivergent and highly stereoselective synthesis of cis- and trans-2-substituted 3-hydroxypiperidines – development of a phosphite-driven cyclodehydration

• Peter H. Huy,
• Julia C. Westphal and
• Ari M. P. Koskinen

Beilstein J. Org. Chem. 2014, 10, 369–383, doi:10.3762/bjoc.10.35

• achieved a yield of 44% over two steps (59% and 74%, respectively) compared to 70% according to our direct conversion from 1a to 2a. Next the carboxylic acids 2 were transformed to the Weinreb amides 5 with DCC and MeONHMe in 77–91% yield (Scheme 2). While no racemisation occurred with substrates 2a, 2b

• carbon (two diastereomers) in the 13C NMR. Additionally, a short 3 step route to the functionalized glutamic and aspartic acid derived Weinreb amides 5e and 5f was coined as outlined in Scheme 3: At the outset both amino acids (1e and 1f) were subjected to esterification of the sterically less hindered

• Weinreb amides 5. Cyclodehydration of amino alcohols 9a–d to piperidinols 11a–d. Cyclodehydration of amino alcohols and diols 12a–h to heterocycles 13a–h. Diastereoselectivity in the reduction of ketone 14a. Supporting Information Supporting Information File 64: Experimental and characterisation data

Efficient synthesis of β’-amino-α,β-unsaturated ketones

• Isabelle Abrunhosa-Thomas,
• Aurélie Plas,
• Nishanth Kandepedu,
• Pierre Chalard and
• Yves Troin

Beilstein J. Org. Chem. 2013, 9, 486–495, doi:10.3762/bjoc.9.52

• reaction of chiral imines with enolates derived from Weinreb amides [13][14]. In previous work on the asymmetric synthesis of 2,6-disubstituted piperidines by C–N bond formation, we demonstrated that intramolecular aza-Michael ”type” cyclisation [15] using a β'-carbamate-α,β-unsaturated ketone

• nucleophilic addition reaction of Grignard reagents to N-carbamoyl β-amino Weinreb amides (Scheme 2) [18]. Conjugate addition of (R)-N-benzyl-N-methylbenzylamide to methyl cinnamate under basic conditions led to β–aminoester 5 with high diastereoselectivity (dr >94%) [11][12]. Subsequent transformation of the

Hybrid super electron donors – preparation and reactivity

• Jean Garnier,
• Douglas W. Thomson,
• Shengze Zhou,
• Phillip I. Jolly,
• Leonard E. A. Berlouis and
• John A. Murphy

Beilstein J. Org. Chem. 2012, 8, 994–1002, doi:10.3762/bjoc.8.112

• ] afforded aryl anions from the same substrates by transfer of two electrons at room temperature, and also cleaved selected sulfonamides [19], bis-sulfones [19], Weinreb amides [22], acyloin derivatives [24], triflate esters and triflamides [26]. Most recently, we announced the synthesis of the unstable

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

• , these two donors can also cleave appropriate arenesulfonamides [25], aryl alkyl sulfones [25][26], Weinreb amides [28] and acyloin derivatives [29]. They are also prone to transfer two electrons rather than one, with the cyclic voltammogram (c.v.) of 8 showing a single 2-electron reversible redox wave