Undecenes reaction

Substituted TMM complexes also cycloadd to aldehydes in the presence of a tin cocatalyst such as MesSnOAc and MesSnOTs [31]. Reaction of 2-heptenal with methyl precursor (6) gave a mixture of methylenetetrahydrofurans (68) and (69). This regioselectivity is reversed with 10-undecenal and methyl precursor (5), where adduct (70) now predominates over (71). As in the carbocyclic system, the phenylthio group also functions as a regiocontrol element in reaction with cyclohexyl aldehyde. The initially formed adduct (72) eliminates the element of thio-phenol on attempted allyl rearrangement, and the overall process becomes a cycloaddition approach to furans (Scheme 2.21) [20]. 

In principle, the quaternization reactions are extremely simple the amine (or phosphine) is mixed with the desired haloalkane, and the mixture is then stirred and heated. The following section refers to the quaternization of l-alkylimidazoles, as these are the most common starting materials. The general techniques are similar, however, for other amines such as pyridine [9], isoquinoline [10], 1,8-diazabi-cyclo[5,4,0]-7-undecene [11], 1-methylpyrrolidine [12], and trialkylamines [13], as... 

PREPARATION OF ALKENES BY REACTION OF LITHIUM DIPROPENYLCUPRATES WITH ALKYL HALIDES ( )-2-UNDECENE... 

Yields of (.E)-2-Undecene Prepared from 1 Equivalent of the indicated Substrates by Reaction Either with 1 Equivalent of Lithium Diproprnyxcuprate or 1 Equivalent of Propenyllithium... 

Entry 4 involves nitrogen participation and formation of an iminium ion that is reduced by NaBH4. The reaction in Entry 5 creates an 11-methylenebicyclo[4.3.1]undecen-3-one structure found in a biologically active natural product. Note that this fragmentation creates a bridgehead double bond. Entry 6 involves construction of a portion of the taxol structure. The reaction in Entry 7 is stereospecific, leading to the E-double bond. 

Z)-l-Nitro-3-nonene is converted into a pheromone, (Z)-5-undecen-2-one, via nitro-aldol reaction (see Section 3.2.3), followed by oxidation, and denitration, as shown in Eq. 7.89.136... 

The same authors have also reported the application of green solvents in additions of terminal alkynes to aldehydes in the presence of Zn(OTf)2 and l,8-diazabicyclo[5,4,0]-7-undecene (DBU, Scheme 109).287 The reactions proceeded very slowly, but afforded desirable alcohols 195 in moderate to good yields. 

Of course, the cleavage reactions of both 2-aryl- and 2-alkyl aziridines are stereoselective because only the trans-diastereomers of the corresponding regioisomers 1 and 2 are formed. In other words, 2-aryl substituted aziridines showed opposite regioselectivity to 2-alkyl aziridines. With bicyclic aziridines, exclusive formation of the trans diastereomer is observed in the case of symmetric bicyclic aziridines. Unsymmetrical aziridines such as styrene, octene, and undecene aziridines produce a minor amount of the other regioisomer. 

Another synthetic route via the Beckmann rearrangement, which is promoted by organoaluminum reagent along with alkylation, involves a new stereoselective reduction of the imino group. The starting oxime sulfonate (228) was synthesized from cyclopentanone (226) in three steps Reaction of 226 with 1-undecene in the presence of silver oxide produced the a-undecylcyclopentanone (227) which on successive treatment with hydroxylamine and methanesulfonyl chlo-ride-triethylamine gave the mesylate (228). Treatment of the oxime mesylate... 

Scheme 9. Reaction conditions i, 1-undecene, Ag20 ii, 130°C, 5 hr iii, NH2OH iv, MsCl-Et3N V, MejAl vi, NaF-H20 vii, LiAlH4-Me3Al.

The 5-tosyloximes of 2,2-dimethyl-l,3-dioxane-4,5,6-trione react with various dienes in a hetero-Diels-Alder-type reaction. The products, aza-dioxaspiro[5,5]undecenes, readily decompose with basic T-chlorosuccinimide to afford 2-carboxypyridines <1998JOC7840>. The same substrates gave with amines cyanoformamides in 43-73% yield (Scheme 22) <2000H(52)283>. 

In the presence of proton and/or Lewis acid and strong nucleophiles bicyclo[3.2.0]heptan-6-ones are converted to 3-substituted cycloheptanones (Table 15). Bicyclo[3.2.0]heptan-6-ones rearrange to give 3-iodocycloheptanones on treatment with iodotrimethylsilane. Zinc(II) iodide or mercury(II) halides as catalysts enhance the rate and the selectivity of the reaction.31 If a second, enolizable carbonyl group is present, an intramolecular alkylation may follow the ring enlargement under these reaction conditions.32 Consecutive treatment with tributyltin hydride/ 2,2 -azobisisobutyronitrile affords reduced, iodo-free cycloheptanones, whilst treatment with l,8-diazabicyclo[5.4.0]undecene yields cycloheptenones.33 Similarly, benzenethiol adds to the central bond of bicyclo[3.2.0]heptan-6-ones in the presence of zinc(II) chloride and hydrochloric acid under anhydrous conditions to form 3-(phenylsulfanyl)cycloheptanones.34... 

The elimination of HX from an alkyl halide is a very general reaction and can be accomplished with chlorides, fluorides, bromides, and iodides.232 Hot alcoholic KOH is the most frequently used base, though stronger bases233 (OR, NH2", etc.) or weaker ones (e.g., amines) are used where warranted.234 The bicyclic amidines l,5-diazabicyc o[3.4.0]nonene-5 (DBN)235 and l,8-diazabicyclo[5.4.0]undecene-7 (DBU)236 are good reagents for difficult cases.237... 

A study using triolein under the same conditions produced seven major volatile compounds from oleate (heptane, octane, heptanal, octanal, nonanal, 2-decenal, and 2-undecenal) as well as other minor components. Addition of stearate to the reaction substrate produced added volatiles previously identified as originating from tristearin alone (Selke et al., 1977). 

In addition to allylic alcohols, other unsaturated alcohols react with halides to give carbonyl compounds. Although the reaction was slow (three days), the reaction of 10-undecen-l-ol (50) with iodobenzene afforded the aldehyde 52 in a high yield. In this... 

Preparation of l-Undecen-4-yne by Reaction of Octynylmagnesium Bromide with Allyl Bromide in the Presence of Copper(I)Chloride... 

Z,5 )-3,5-Tetradecadienyl acetate 284 was recently presumed to be the pheromone of Prionoxystus robiniae on the basis of electronantennogram data it could be synthesized via Wittig reaction of ( )-2-undecenal 282 and the ylide 283. (3Z,5 )-3,5-tetradecadienyl acetate 284 was separated from its distillation residue [98% (3E,5E)-3,5-isomer] with 95 % purity by means of spinning ribbon-column distillation 196> (Scheme 52). 

The cross-coupling of allylsilanes with alkenes [50] and styrene [58] also occurs via their preliminary isomerization followed by the reaction of 1-propenylsilane with exemplary olefin-l-decene resulting in l-(triethoxysilyl)-1-decene as a product (Eq. 31). If the cross-coupling takes place, an expected product of this reaction is l-silyl-2-undecene, which is not detected. 

Chapter S you met the bases DBU (l,8 diazabicyclo[5.4.0]undecene-7) and DBN (l,5-diazabicycio[3.4.0]nonene-5) named in the same way—and you will meet them again in the very next chapter, as they are particularly good bases for the promotion of elimination reactions. 

Chalcones can be prepared by a Heck reaction between an aryl iodide and an aryl vinyl ketone. Demethylation allows spontaneous cyclisation to the flavanone <03TL9107>. An arene-alkene photocyclisation is observed during the irradiation of dihydro-2-methyl-2-vinylnaphtho[l,2-6]pyran-4-one and benzotricyclo[5.3.1.0 ]undecenes 24 result <03TL2011>. 

Moreover, starting from 2,9-dimethyl-10-undecene-4,6-diol (3), the alkoxycarbonylation reaction results in the corresponding tetrahydro-2//-pyran 4 in moderate yield and a cis/trans ratio of 89 1183. 

Furthermore, the double-bond configuration strongly influences the stereochemical outcome of 5-alkenol cyclization. Thus, starting from ( )-2-methyl-9-undecen-5-ol [( >8], the 2,6-c/j-te-trahydro-2//-pyran-2-acetate 9A is the major component of the reaction mixture, whereas starting from (Z)-8 the 2,6-trfliw-derivative 9C is exclusively obtained82. 

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