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Several amino acid ester hydrochlorides were reacted with ammonium formate to give N-formyl amino acid esters in good yields. 相似文献
2.
An efficient method for N-alkylation of diethyl acetamidomalonate (DEAM) is reported. C-Alkenylation was achieved by treating the N-alkenylated DEAM with various electrophiles in the presence of Cs2CO3. RCM reactions of C- and N-alkenylated products gave cyclic amino acid derivatives in good yields. 相似文献
3.
Sambasivarao Kotha Vittal Seema Kuldeep Singh Kodand Dinkar Deodhar 《Tetrahedron letters》2010,51(17):2301-421
Highly functionalized cage compounds have been prepared via cross-metathesis (CM) using Grubbs modified N-tolyl catalyst 7. A strategic utilization of photo-thermal metathesis and catalytic metathesis sequence for the synthesis of functionalized caged molecules has been demonstrated. 相似文献
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Formation of three diasteroisomeric spirodilactones 14a-c and 11 has been reported from diester 13 and 9, respectively, under the influence of mineral acid. 相似文献
5.
Olefin metathesis promoted by a well-defined metal carbene complex has evolved into an efficient method for the construction of a broad range of carbocyclic and heterocyclic rings of varying size. The synthetic potential of the olefin metathesis has been further increased by combining various other C-C bond forming processes either in tandem or in sequence. Herein, application of Claisen rearrangement and olefin metathesis to prepare various intricate and/or biologically important targets has been described. 相似文献
6.
Sambasivarao Kotha Enugurthi BrahmacharyAtsuo Kuki Kamil Lang Demetrios AnglosBakthan SingaramWilliam Chrisman 《Tetrahedron letters》1997,38(52):4290
A novel constrained 7-amino-6,7-dihydro-8H-cyclopenta[g]quinoxaline-7-carboxylic acid derivative was prepared starting from 4,5-dimethyl-o-phenylenediamine. 相似文献
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We have demonstrated a useful synthetic strategy to assemble star-shaped C3-symmetric molecules containing 1,3-azole moieties at the periphery. To generate these C3-symmetric heterocycles, we have employed the Pd/Cu-based coupling reactions. To this end, we have used benzoxazole, benzothiazole, and benzimidazole as coupling partners to generate the corresponding hetero-aryl Heck coupling products. 相似文献
8.
Several functionalized cage propellanes and D3-trishomocubanes containing spiro linkage have been reported starting with commercially available materials such as 1,4-hydroquinone and dicyclopentadiene. In this regard, Claisen rearrangement, Diels–Alder reaction (DA), ring-closing metathesis (RCM) and acid-promoted rearrangement have been used as key steps. The strategies described here, opens up new opportunities to assemble intricate cage systems that are difficult to construct by conventional methods. Carbocation intermediates generated during the rearrangement process play a prominent role in designing unusual cage systems. One of the rearranged cage compound's structure was unambiguously established by single crystal X-ray diffraction studies. 相似文献
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Several new synthetic methods to diverse polycycles and heterocycles on the basis of [3,3]‐sigmatropic rearrangement and ring‐closing metathesis as key steps are summarized. In this regard, Claisen, aza‐Claisen, and Overman rearrangements are used in combination with other popular reactions such as ring‐closing metathesis, Suzuki coupling, Diels–Alder reaction, and retro‐Diels–Alder reaction. To this end, we prepared polycycles (e.g., cyclophanes, cage molecules), heterocycles (e.g., oxepins, azapins), carbocycles, and spirocycles with the use of the above protocol. 相似文献