Propane, reactions with

Catalysts of the Co(salen) family incorporating chiral centers on the ligand backbone are useful in asymmetric synthesis and the field has been reviewed.1377,1378 In two examples, the hydroxy-lation reaction (Equation (14)) involving (269) proceeds with 38% ee,1379 whereas the cyclo-propanation reaction with (271) (Equation (15)) proceeds with 75% ee and with 95 5 trans cis.1380 A Co(V) salen carbenoid intermediate has been suggested in these reactions. 

In close structural analogy to the semicorrinate ligands of 9, the bidendate, chiral C2-symmetric 5-azasemicorrins 10216 and bis(4,5-dihydrooxazol-2-yl)methane systems li,196 217 12,218 219 12a,197 13,220 and I4197a perform exceptionally well in copper-catalyzed enantioselective cyclo-propanation reactions with diazo esters. With 10, 11, and 12 a, the active catalyst is prepared in situ by adding a catalytic amount of a copper(I) salt with a weakly coordinating anion [copper(I) triflate,196,217,219 copper(I) perchlorate197] to the free ligand with the enolizable system 12 (as well as with 12a and 14) it has been prepared by reaction with copper(I) terh butoxide or from the copper(I) bischelate complex by reduction with phenylhydrazine. 

The alcohol intermediate happens to be the exact kind of intermediate that was produced by the Grignard reagent reaction with propanal to produce isosafrole back-a-ways in the big chapter. So what the chemist does is apply the 1g of KHSO4 to that crude alcohol intermediate and process it just as was done before to give isosafrole, or propenylbenzene or 3,4-methylenedioxyphenyl -1-butene or phenylbutene (yield=91% ). This is a great little procedure. 

Fig. 3. Synthesis of fluoxetine (31). 3-ChIoro-I-phenyl-I-propanol reacts with sodium iodide to afford the corresponding iodo derivative, followed by reaction with methylamine, to form 3-(methyl amin o)-1-phenyl-1-propan 0I. To the alkoxide of this product, generated using sodium hydride, 4-fluorobenzotrifluoride is added to yield after work-up the free base of the racemic fluoxetine (31), thence transformed to the hydrochloride (51)...

Reactions other than those of the nucleophilic reactivity of alkyl sulfates iavolve reactions with hydrocarbons, thermal degradation, sulfonation, halogenation of the alkyl groups, and reduction of the sulfate groups. Aromatic hydrocarbons, eg, benzene and naphthalene, react with alkyl sulfates when cataly2ed by aluminum chloride to give Fhedel-Crafts-type alkylation product mixtures (59). Isobutane is readily alkylated by a dipropyl sulfate mixture from the reaction of propylene ia propane with sulfuric acid (60). 

In the second paper the models were amplified for ethane, 49 reactions with 11 molecular species and 9 free radicals for propane, 80 reactions with 11 molecular species and 11 free radicals. The second paper has a list of 133 reactions involving light hydrocarbons and their first- or second-order specific rates. 

An illustration of the tendency of alkane 1,2- and alkane-1,3-dicarboxylie acids to a ring closure during the reaction with sulfur tetrafluoride is the reaction of propane-1,2,3-tricarboxylie acid The corresponding six- and five-membered cyclic ethers are formed in a 1 4 ratio [211] (equation 106)... 

Knef and coworkers have fouad that 2-lithio-2-sulfoaylpropane and 2-lithio-2-nitropropane behave differenlly in the addition to dimethyl alkylidenemalonate. Thus, 2-Lithio-2-snlfonyl-propane reacts with it iiimost exclusively on the CSii-face and leads to the ruin -addnct, whereas 2-lithio-2-nitropropane reacts under similar reaction conditions, exclusively on the Wfi -face, providing the iy)i-prodnct fEq. 4.134. ... 

One molecule (or mole) of propane reacts with five molecules (or moles) of oxygen to produce three molecules (or moles) or carbon dioxide and four molecules (or moles) of water. These numbers are called stoichiometric coefficients (v.) of the reaction and are shown below each reactant and product in the equation. In a stoichiometrically balanced equation, the total number of atoms of each constituent element in the reactants must be the same as that in the products. Thus, there are three atoms of C, eight atoms of H, and ten atoms of O on either side of the equation. This indicates that the compositions expressed in gram-atoms of elements remain unaltered during a chemical reaction. This is a consequence of the principle of conservation of mass applied to an isolated reactive system. It is also true that the combined mass of reactants is always equal to the combined mass of products in a chemical reaction, but the same is not generally valid for the total number of moles. To achieve equality on a molar basis, the sum of the stoichiometric coefficients for the reactants must equal the sum of v. for the products. Definitions of certain terms bearing relevance to reactive systems will follow next. 

A major use of propane recovered from natural gas is the production of light olefins by steam cracking processes. However, more chemicals can be obtained directly from propane by reaction with other reagents than from ethane. This may be attributed to the relatively higher reactivity of propane than ethane due to presence of two secondary hydrogens, which are easily substituted. 

Excellent double diastereoselection has also been realized in the reactions of (7 )-2,3-[isopro-pylidenebis(oxy)]propanal and chiral 2-butenylboron reagents (Table 8). The best selectivity for the (3R,4R)- and (SS /Q-diastereomers was obtained by using the tartrate ( )- and (Z)-2-butenylboronates. (S.S -D and (R,R)-D, respectively69,81, while (E)- and (Z)-2-butenyl-2,5-dimethylborolane reagents (R,R)-C and (S,S) C provided the greatest selectivity for the (3S, 45)- and (3y ,4S )-diastereomers< 9. Comparative diastereoselectivity data for reactions with the achiral (E)- and (Z)-2-butenyl-4,4,5,5-tetramethyl-l,3,2-dioxaborolanes have also been provided in the table. 

Z)-l-Methyl-2-butenylboronate 7 undergoes an exceptionally enantioselective reaction with benzaldehyde (99% ee), propanal (79%. 98% ee), 2-methyl-2-propenal (85%, 99% ee), and ( )-2-methyl-2-pentenal (81 %, 99% ee)10 38. Excellent enantioselectivity is also realized in reactions of the analogous chiral a-methyl-) y-disubstituted allylboronate27 40. Whether the l,2-dicyclohexyl-l,2-ethanediol auxiliary plays a beneficial role in this reaction, as suggested above for the asymmetric allylboration reactions of 6, has not yet been determined. 

The data summarized in Section 1.3.3.3.3.2.3. established that a-chloro-2-propenylboronate 2 is more enantioselective than l9,32a b. It is not surprising, therefore, that the reactions of 2 and chiral aldehydes exhibit greater diastereoselectivity, particularly those cases involving mismatched double diastereoselection. This point is demonstrated by the reactions with (i )-2,3-[isopropylidenebis(oxy)]propanal. 

The matched double asymmetric reactions with (7 )-l and (a.R,S,S)-2 provide the (S,Z)-diastereomer with 94% and 96% selectivity, while in the mismatched reactions [(S)-l and (aS,R,R)-2] the (S.Z)-diastereomer is obtained with 77% and 92% selectivity, respectively. Interestingly, the selectivity of the reactions of (/ )-2,3-[isopropylidenebis(oxy)]propanal and 2 is comparable to that obtained in reactions of (7 )-2,3-[isopropylidenebis(oxy)]propanal and the much more easily prepared tartrate ester modified allylboronates (see Table 7 in Section 1.3.3.3.3.1.5.)41. However, 2 significantly outperforms the tartrate ester allylboronates in reactions with (5)-2-benzyloxypropanal (Section 1.3.3.3.3.1.5.), but not the chiral reagents developed by Brown and Corey42-43. 

As an example that uses structural formulas and Equation, consider the energy change that takes place during the combustion reaction of propane (C3 Hg). Recall from Chapter 3 that combustion is a reaction with molecular oxygen. The products of propane combustion are carbon dioxide and water ... 

The first two reaction types often lead to the formation of stable end-products, but (c) and (d) lead to the formation of new carbocations to which the whole spectrum of reaction types is still open. Most of these possibilities are neatly illustrated in the reaction of 1-amino-propane (11) with sodium nitrite and dilute hydrochloric acid [the behaviour of diazonium cations, e.g. (12), will be discussed further below, p. 119] ... 

Type (b) reaction on this rearranged cation (16) will yield more propene (15), while type (a) reaction with water will yield propan-2-ol... 

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