Michael approach

Figure 15.23 Tetrahydroquinoline-based p-amino acids synthesized by an asymmetric hetero-Michael approach.

Figure 15.25 Model studies regio and stereoselective hetero-Michael approach to tetrahydroquinoline-based polycyclics.

Fig. 17.7 Solid phase synthesis to obtain aminoindoline alkaloid-like tricyclic compounds by in situ aza Michael approach - (a) alkylsilyl linker-based polystyrene macrobeads (1.0 equiv),TfOH (6.0 equiv), 2,6-lutidine (10.0 equiv), 14 (0.5 equiv) (b) (i) 20% piperidine (ii) N-Fmoc amino acid chloride, collidine (iii) 20% piperidine.

Fig. 17.12 In situ bridged aza Michael approach in solution and on solid phase to obtain tetrahydroquinoline-based tricyclic compounds, (a) (i) acetic acid/THF/H20, RT (ii) TESOTf, pyridine, CH2CI2, -40°C (iii) Pd(PPh3)4, morpholine, CH2CI2, RT (c) Et3N, benzoyl chloride or cinnamoyl chloride, CH2CI2, O C to RT.

Prakesch, M., Srivastava, S., Leek, D. M., Arya, P. (2006) Part 3. A novel stereocontrolled, in situ, solution- and solid-phase, aza michael approach for high-throughput generation of tetrahydroaminoquinoline-derived natural-product-like architectures. Journal of Combinatorial Chemistry, 8, 762-773. 

Brochu, J.L., Prakesch, M., Enright, GJ5., Leek, D.M., and Arya, P. (2008) Reagent-based, modular, tandem Michael approach for obtaining different indoline alkaloid-inspired polycyclic architectures. Journal of Combinatorial Chemistry, 10, 405-420. 

Scheme 58 Brimble et al. s oxa-Michael approach toward bis(henzannulated) sprroacetals [127]...

The authors are indebted to Professor Michael Baer for many years of exciting collaboration, to Dr. B. Halperin for advice, to F rofessor Mark Pere lmanfor discussion and permission to quote from his preprint Temporal Magnitudes and Functions of Scattering Theory, to Professor Shmuel Elitzur for suggesting the approach leading to Alternative Derivation in Section V and to Professor Tgal Talmi for an inspiration [327],... 

A similar approach is followed in a recent study of the Lewis-acid catalysis of a Michael addition in acetonitrile. See Fukuzumi, S. Okamoto, T. Yasui, K Suenobu, T. Itoh, S. Otera, J. Chem. Lett. 1997, 667. 

Each of these approaches may be the best for any given lactone the one in the last frame for example would allow you to use any Michael acceptor and any aldehyde. 

Another approach to processible bismaleimide resins via a Michael addition chain extension, is the reaction of bismaleimide, or alow melting mixture of bismaleimides, with aminobenzoic hydrazide to provide a resin that is soluble in various solvents, such as acetone [67-64-1methylene chloride [75-09-2] and dimethylform amide [68-12-2] (33). The idealized chemical stmcture for a 2 1 BMI—aminobenzoic hydrazide resin is as follows ... 

An interesting approach to thermosetting acetylene-terminated polyimides via the Michael addition reaction has appeared (38). Acetylene-terminated aspartimides are readily prepared ia high yield via two routes, shown ia Figure 7. 

Unfortunately, much of Fiesselmann s work was documented only in patents and doctoral theses, allowing for the rediscovery of this classic reaction in recent years. In fact, as late as 1997, the Fiesselmann reaction of 5 with methylthioglycolate was rediscovered as a novel, tandem Michael addition/intramolecular Knoevenagel approach to thiophenes such as 6 ... 

Another approach is the Michael addition to ethyl (3-nitroacrylate, as shown in Eq. 7.123, which has been used in the synthesis of a-methylenebutyrolactone, a moiety characteristic of many sesquiterpenes. ... 

An interesting approach to zr n.v-2,3-disubstituted cyeloalkanones is offered by auxiliary controlled intramolecular Michael additions. The diastereoselectivity depends on the chiral alcohol used193> l94. When the borneol derivative 7 was used as substrate, a single diastereomer of 8 resulted when the reaction was performed at 25 "C under thermodynamic control with a catalytic amount of sodium hydride in benzene. 

Methods for the catalytic enantioselective Michael addition have been developed using three different approaches ... 

A general approach to the synthesis of enantiomerically pure y, as weU as y " -amino acids has been developped by Brenner and Seebach [206, 207, 230]. It involves the Michael addition of Ti-enolates generated from acyl-oxazohdin-2-ones to nitroolefms in the presence of a Lewis acid (TiCU, Et2AlCl) as the key step... 

A more logical approach was to adjust the oxidation level of (23) and to reconnect in the manner of (17a) to give symmetrical (26), easily made by a Michael addition. 

Kinetic, spectroscopic, and enantioselectivity data provided strong evidence for a mechanism involving bimetallic catalysis. The configurational outcome depends upon the face selectivity of the enol approaching the Michael acceptor in 59 (Fig. 32). To differentiate between the enantiotopic faces, the catalyst has thus... 

Ye and co-workers have shown that NHC 67 can catalyse the aza-Morita-Bay-lis-Hillman reaction of enones 66 and N-tosyl imines 63, presumably via initial NHC conjugate addition to the enone to generate an azolium enolate 68 [18]. A related conjugate addition approach has been exploited by Fu and co-workers, with tautomerisation of the initial enolate 72 derived from NHC conjugate addition to 70 giving 73, with subsequent cyclisation resulting in the umpolung of Michael acceptors (Scheme 12.13) [19]. 

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