Nitroalkene synthesis

Enders, D. Meyer, O. Raabe, G. Diastereo-and enantioselective synthesis of 4-nitrocydo-hexanones by [4 + 2] cycloaddition of a chiral 2-aminobutadiene to nitroalkenes. Synthesis 1992, 1242-1244. 

Alkenes can be nitromeicurated (HgQ2/2 NaNOs/H20, 30 h, 25 Q and the products can be bromo-demercurated, giving bromonitro compounds. An alternative woik-up with base provides a valuable nitroalkene synthesis (Scheme 84). °... 

Nitroalkene Synthesis. Henry reaction of (phenylthio)nitro-methane with aldehydes fohowed by dehydration has been used to prepare (. -l-nitro-l-phenylthioalkenes. potassium 7eri-butoxide-catalyzed addition and dehydration via mesylation (eq 1), or direct condensation catalyzed by piperidinium acetate (eq 2), are the methods of choice. Henry reaction can be also carried out by reaction of the nitroalkene dianion with aldehydes. ... 

The Barton-Zard (BZ) pyrrole synthesis is similar both to the van Leusen pyrrole synthesis that uses Michael acceptors and TosMlC (Section 6.7) and the Montforts pyrrole synthesis using a,P-unsaturated sulfones and alkyl a-isocyanoacetates." An alternative to the use of the reactive nitroalkenes 1 is their in situ generation from P-acetoxy nitroalkanes, which are readily prepared via the Henry reaction between an aldehyde and a nitroalkane followed by acetylation. Examples are shown later. 

In 1985, in the course of their interest in nitroalkane chemistry, Barton and Zard reported the base-catalyzed reaction of nitroalkenes with a-isocyanoacetates leading to pyrrole esters having an ideal substitution pattern for the synthesis of porphyrins and bile... 

The synthesis of cyclic nitroalkenes via nitradon of cyclo ilkenes is sttmmarized in Table 3 3 Acyclic nitro ilkenes are more readily prepared via the Henry reacdon than by nitradon of ilkenes fsee Secdon 3 3 1 ... 

OxiddQon of oximes to rutro compounds with w-CPBA has been applied to the synthesis of dialkyl l-nitroalkanephosphonates fEq 2 63, which are useful reagents for d carbonyl compounds to nitroalkenes... 

A stereospecific total synthesis of polyoxin C and related nucleosides is reported, in which thereacdon of l-Cphenylthioi-l-nitroalkenes v/ith nucleophiles and siibseqiientozono lysis are key reacdons Addidonof potassium trimethylsilanoate to l-Cphenylthioi-nitroalkenes derived from D-ribose followed by ozonolysis gives the cr-hydroxy thioester, which is formed v/ith excellent diastereoselecdvity fScheme 4 5 This conformadon meets the stereo-electronic requirements for andperiplanar addition of the nucleophile with the result of high 5-fS stereochemical bias in the reacdons... 

Jackson and coworkers have used a new approach to the synthesis of fi-hydtoxy-ct-amino acids using farylthio nitrooxiranes. c-Jsopropylideneglyceraldehyde is converted into the corresponding 1-arylthio-l-nitroalkene, which is a key material for stereoselective synthesis of fi,Y-dihydroxyamino acids fScheme 4.6. The key step is stereoselective nucleophilic epoxlda-donof the Tarylthio-Tnltroalkene. Sy)i and ruin epoxides are selecdvely obtained by appropriate choice of epoxidadon reagent." ... 

A short synthesis of ptostaglandm derivatives via a three component coupling reaction reported, in which the enolates are trapped v/ith nitroalkenes. The nitro group is removed v... 

This procedure Is applied to synthesis of 1,3-diamines by the addition ofmetdlated rerr-biityl iV.iV-dimethylcarbamate to nitroalkenes and subsequent reduction fEq. 4.84. ... 

The Michael addition of the copper-zinc reagent derived from ethyl 4-bromobntyrate to the plperonal-derived nitroalkene proceeds cleaniy to give the nitre ester, which is an intermediate for the synthesis of lycoricidine alkaloids fEq. 4.85. ... 

The direct conversion of nitroalkenes into ketones is especially useful for the preparation of arylacetones. They are readily prepared by the condensation of aromatic aldehydes with nitroethane and by the subsequent Nef reaction. "Typical examples are presented in Eq. 6.22 and Eq. 6.23 the product of Eq. 6.23 is used for total synthesis of perylenequinone, calphosdn D, which is a potent inhibitor of protein kmase C. "... 

An intramoleculdf raLliciil cyclizdDon gives ihe exa-cyclic compounds, which has been extensively used in the synthesis of cychc compounds Michael adthdons of allyl idcohols or propargyliilcohols to nitroalkenes and the subsequent treatment v/ilhdn rathciils provide a useful method for the preparadon of sitbsdrtited ftirans fEqs 7 83 and 7 84 ... 

Functionalized nitroalkenes are important chenophiles in the Diels-Alder ri example, fE -methyl fi-nitroactylate is an impottant reagent in organic synthesis The nitre group can be readily eliminated the Diels-Alder reaction of fi-nitroactylate is equivalent to that of ethyl propiolate with an inverse regiochemistry fEq. 8.4. ... 

Node and co-workers have found that the Diels-Alder reaction of nitroalkenes v/ith 1-methoxy-3-trimethylsilyloxy-l,3-butadiene (Danishefsky s dienesi exhibit abnormal exo-se-lecdvity Electrostadc repulsion between the nitro and the silyloxy group of the diene induces this abnormal exc-selecdvity (Tq 8 10 This selecdve reacdon has been used for the asymmetric synthesis of various naniral products as shovm in Scheme 8 6... 

The Diels-Alder reaction of nitroalkenes with Danishefsky s dienes is applied to synthesis of truncated carbocyclic analogues of a potent neuraminidase inhibitor 4-guanidino-NemAc en fsee Scheme 8.5. Carbocyclic analogs are found to retain interesting levels of antiviral activity comparable to those shovm by their oxygen-containing compounds in Scheme 8.5. 

Node and coworkers have used this aromadzadon strategy for the synthesis of (-) aphanor-phineThe Diels-Alder reacdon of chiral nitroalkene, prepared by the asymmecdc nitrooleft-nation reacdon of ct-methyl-o-valerolactone, with the Danishefsky s diene followed by aromadzadon is used as a key step for this total synthesis, as shown in Scheme 8 6... 

Node and Fuji have developed a new chiral synthesis of various alkaloids using chiral nitroalkene, fS -( - -3-methyl-3-( 3 -nitrovinyl -o-valerolactone Scheme 8 11 shows a total synthesis of f-i-physosdgmine, a principM alkriloid of the CMabar bean The key nitroalkene is prepared by asymmetric nitroolefinadon of ct-methyl-o-lactone using a chirM enamine fsee... 

The introducdon of heterodienes has extended the synthedc versatility of cyclokldmon teac-dons in organic synthesis. " Denmark and coworkers have developed the use of rutroalkenes as dienes in [4+2 cycloaddidon. Nitroalkenes react v/ith simple alkenes in the presence of SnCi, as a promoter. For example, the reacdon of tutrocyclohexene v/ith cyclopentene gives three products. The major product is ruiri-isoraer, which arises from an fixn approach of cyclopentene toward tutrocyclohexene fsee Eq. 8.94. ... 

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