Michael addidon

Synthesis of thiopheno[3,4-c isoxa2olide is shown in Eq. 4.4, in which the Michael addidon of allyl thiol to fi-nitro enones and subsequent nitnle oxide cyclizadon are involved. ... 

The Michael addidon of allyl Mcohols t nitronate olefin cycloaddidon fSecdon 8.2, 4.15. ... 

The Michael addidon of nitroalkanes to nitroalkenes is catalyzed by triethylamine to give 1,3-dirutro compounds fEq. 4.45. In some cases, the intramolecular displacement of thenitro group takes place to give cyclic nitronates fEq. 4.46. ... 

Enandoselecdve synthesis of the anddepressant rohpram can be done by the asymmetric Michael addidon of the enolate of iV-acetyloxa2ohdone to nitrostyrene, Chiially branched pyrrohdones like rohpram are highly acdve anddepressants v/ith novel postsynapdc modes of acdon. The synthesis is shown in Scheme 4,13, ... 

The chiral enamines provide the opportunity for the enandoselecdve Michael addidon to nitroalkenes, as shown in Eq. 4.68, where the ketone is obtained as a single diastereomer with anee>90%. ... 

In Table 4 1, the Michael addidon of nitto compounds to various electron deficient alkenes is shovm... 

The Michael addidon of nitto compounds is a useful method for the preparadon of various naniral products The Michael kldidon of nittoalkanes to dehydroalanines gives ynitto-ct-amino acids, which provides a convenient synthesis of side-chain modified ct-amino acids fEq 4 114 " Transformadons of Y-nitto-ct-amino acid derivadves into ct-amino adds occur by... 

A short enandoselecdve synthesis of f- -f/f,/f -pytenophorin, a naturaUy occurring and-fun-giil 16-membered macrohde dilactone, is prepared from fS -5-nitropentan-2-ol via the Michael addidon and Nef reacdon fScheme 4.23. The choice of base Is important to get the E-alkene in the Michael addidon, for other bases give a rruxture of and Z-alkenes. The reqidslte chiriil fS -5-nitropentan-2-ol Is prepared by enandoselecdve redncdon of 5-nitropentan-2-one v/ith baker s yeast. ... 

Polyfiincdonalizeduitro compounds are prepared by the Michael addidon using 2-alkenyl-snbsdtiited 2-siloxycyclopropiinecarboxylates as Michael acceptors fEq. 4.120. ... 

Newkoine ind co workers have developed synthesis of dendndcinolecides using the Michael addidon of uitroinethiine to a,fi-iinsatiirated estets as a key reacdon fScheine 4.24. ... 

Barco and coworkers have reported a more elegant synthesis of the nitrocyclohexan the double Michael addidon of nltromethane with enones. fEq. 4.130. ... 

Interesdng intramolecular cycllzadon of Tnitroalkyl radicals generated by one-electron oxidadon of nci-nitro anions vrith CAN is reported. As shown in Eq. 5.44, stereoselecdve formadon of 3,4-funcdonalized tetrahydroflrtans is observed. TNitro-6-heptenyl radicals generated by one electron oxidadon of aci-nitroanions vrith CAN afford 2,3,4-trisnbsdtuted tetrahydropyrans. The requisite nitro compounds are prepared by the Michael addidon of 3-buten-Tal to nitroalkenes. 

Furthermore, a neighboring group participadon of a phenylthio funcdon is observed in the Lewis acid-catalyzed nucleophiEc subsdnidon reacdon of various fi-nitrosulfides. Because the fi-nitrosulfides are readily available, by the Michael addidon of thiols to nitroalkenes fsee Michael addidon Chapter 4, this reacdon is very useful. The fi-nitrosulfides are prepared stereoselecdvely, and the reacdon proceeds in a stereo-specific way fretendonof configiuadoni as shown in Eqs. 31 -34. 

Alttmina-supported KF is an effecdve reagent for Michael addidon of nitroalkanes to electron-deficient olefins. Subsequent cycloalkyladons afford cyclopropanes.However, the reacdo n of a,fi-ttnsantrated ketones v/ithnitroalkanesin the presence of KF-A1,0 in acetonitrile gives 4,5-dihydrofliranes fEq. 7.39. ... 

The Michael dclclidon of nitro ilkdnes followed by denitration is also a useful method fot the pteparadon of C-disaccharide. The Michael addidon of glncosyl nitromethane to the levogln-cosenone ptoceeds steteoselecdvely, and subsequent denitradon gives the C-disaccharide in 68% yield fScheme 1.%) ... 

Elegant apphcadon of the Michael addidon of nitro ilkanes to enones followed by denitradon is demonstrated in the synthesis of (+) dihydromevinol, fsee Scheme 7.9 ... 

The high acidity of ct-nitroketones makes it possible to perform the Henry reacdons or Michael addidons under extremely rruld condidons The reacdon proceeds in the presence of catalydc amounts of Ph-vP to give the C-C bond formadon products under nearly neutral condidons Thus, 1,5-dicarbonyl compounds and ct-methylenecarbonyl compounds are prepared by the denitradon of ct-nitroketones, as shown in Eqs 7 67 and 7 68, respecdvely... 

Balhni and coworkers have reported a simple synthesis of Tphenylheptane- 1,5-dione based on the strategy of the Michael addidon and denitradon as shown in Eq 7 69 The product is a natural product that is isolated from fungus... 

The Michael addidon of heteroaiom nucleophiles to nitro ilkenes fSecdon 4.1.1 followed by denitradon provides a usefid method for the preparadon of various naairal products. 

Seqnendal Michael addidons are versatile methods for the constnicdon of cyclic compounds. Although a variety of these reacdons have been developed, the use of alcohols as nucleophiles for the Michael addidon to nltroalkenes has been little studied. Recently, Dteda and coworkers have reported an elegant synthesis of octahydtobett2o[li furans via the seqnendal Michael addidon of 1-nltro-cyclohexenev/ith methyl4-hydroxy-2-bittynoatein the presence of r-BnOK followed by radical denitradon fEq. 7.74. ... 

Amino-subsdnued dienes are also important dienophiles in Diels-Alder reactions Recently, chiral and achiral 2-amino-l,3-dienes have been prepared to snidy their reactivity Csee also asymmetric Diels-Alder reaction Section 8 1 2 The reaction of 2,3-diamino-l,3-butadienes v/ith nitrostyrene gives unusual [3t-2 carbocyclization products, 2-aminocyclopentanones, which are not formed by the direct cycloaddidon but derived from the Michael addidon products fsee secdon discussing the Michael addidon Secdon 4 1 3 "... 

Nitroedianeundergoes base-catrilyzed addidon to to give3-hydroxy-l,3-dihydrofu]leryl ketoxime by way of a unique intramolecidar redox process, which is not observed in normal electron deficient alkenes fEq. S.77. " FSee Secdon 4.3 Michael addidon of nitroalkanes. ... 

Another pyrrole synthesis based on intramolecidar subsdnidon of the nitro group by amino funcdon is presented in Eq. 10.7, in which the Michael addidon of enamines to nitroalkenes is... 

The Michael addidon to nitroalkenes followed by cyclizadoti provides a getieriil method for the synthesis of various pyrroles. The reacdoti of nitroalkenes v/iih acetoacetate followed by reducdoti v/ith Znin acedc acid provides another route to 3-methyl-3-pyrrolecarboxylates fEq. 10.8. °... 

Nitro compounds have been extensively used for synthesis of pyrrolidines as discussed in Chapter 4 on the Michael addidon and Chapter 8 on cycloaddidon. Tandem [2 + 4 /[2 + 3 ... 

N. Kawauchi, K. Sato, J. Yoshimura, and H. Hashimoto, Synthesis of 2,2-di-C-methyl-2-deoxy- and 4,4-di-C-methyl-4-deoxypranosides via Michael addidon of conjugated eno-pyranosiduloses. Bull. Chem. Soc. Jpn 60 1433 (1987),... 

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