Allyl-diethyl

Allylamines are not easily cleaved with Pd catalysts, but the carbonylation of the allylic amine 395 proceeds at 110 C to give the /3,7-unsaturated amide 396 by using dppp as a ligand[252], Dccarboxylation-carbonylation of allyl diethyl-carbamate under severe conditions (100 C, 80 atm) affords /3,7-unsaturated amides[2531. The 3-vinylaziridine 397 is converted into the a-vinyl-J-lactam 398 under mild conditions[254]. 

HsCjljN-MgBr 30 25 Bis-[2,4-pentandionato]-palladium Allyl-diethyl-amin 96 8... 

Allyl-phenyl-ether und Diallyl-ether werden in ahnlicher Weise gespalten, und zwar durch Diethylaminomagnesium-bromid unter Bildung von Allyl-diethyl-amin und durch Bis-[brommagnesium]-alkyl- (bzw. phenyl)-amin (in situ aus primarem Amin und Alkylma-... 

The palladium-catalyzed carbonylation reaction of allyl diethyl phosphate, in the presence of imines, gives either cis- or rraws-3-vinyl-/J-lactams, in high yields and in a stereoselective fashion (equation 160)574,575. The reaction is a [2 + 2] cycloaddition process which occurs under simple and mild conditions and has significantly more potential than the reaction of imines with ketenes (due to the more forcing conditions that are usually required to form the ketene intermediates). This reaction, however, only proceeds in low yield if the allyl phosphate is replaced with allyl acetate576. 

Alkylation and animation ofallylie phosphates.6 Allyl diethyl phosphates undergo efficient allylie alkylation and animation in the presence of this Pd(0) catalyst. Examples ... 

Stibonium Allyl-diethyl-methyl-(jodid) XI11/8, 571... 

Ci2H2oSi 5-(allyl-diethyl-silanyl)-cyclopenta-l,3-diene 67918-57-4... 

Stereoselective syntheses of (ff)-olefinic derivatives have been developed by alkylation of allyl diethyl phosphonates followed by reduction with lithium aluminium hydride.Both E)- and (z)-olefinic derivatives have been obtained from acetylene precursors by reduction with either lithium aluminium hydride or in presence of Lindlar catalysts. ... 

To expand the range of phosphates for preparation of organomanganese phosphates, alkyl-, phenyl-, and allyl diethyl-phosphates were attempted. Unfortunately, the oxidative addition of active manganese (Mn ) to these phosphates and the subsequent coupling reactions with electrophiles foiled to give the corresponding cross-coupled products. 

In another example, Pd2(dba)3 was used in conjunction with allyl diethyl phosphate, an unusual stoichiometric hydrogen acceptor in the oxidation of simple alcohols. Oxidative addition of Pd(0) into the allylic phosphate (generating a r-allyl-Pd(II) complex), is followed by an alcohol/phosphate displacement and subsequent /3-hydride elimination giving the oxidized alcohol... 

Both primary and secondary alcohols can be converted into the corresponding aldehyde or ketone by a method using allyl diethyl phosphate, as hydrogen acceptor, in combination with either potassium or sodium carbonate and Pd(OAc)2 as catalyst. For example, 2-octanone and cirmamaldehyde have each been synthesized by this route, and in yields of 85 and 90%, respectively. ... 

Dramatic rate accelerations of [4 + 2]cycloadditions were observed in an inert, extremely polar solvent, namely in5 M solutions oflithium perchlorate in diethyl ether(s 532 g LiC104 per litre ). Diels-Alder additions requiring several days, 10—20 kbar of pressure, and/ or elevated temperatures in apolar solvents are achieved in high yields in some hours at ambient pressure and temperature in this solvent (P.A. Grieco, 1990). Also several other reactions, e.g, allylic rearrangements and Michael additions, can be drastically accelerated by this magic solvent. The diastereoselectivities of the reactions in apolar solvents and in LiClO EtjO are often different or even complementary and become thus steerable. 

The first practical method for asymmetric epoxidation of primary and secondary allylic alcohols was developed by K.B. Sharpless in 1980 (T. Katsuki, 1980 K.B. Sharpless, 1983 A, B, 1986 see also D. Hoppe, 1982). Tartaric esters, e.g., DET and DIPT" ( = diethyl and diisopropyl ( + )- or (— )-tartrates), are applied as chiral auxiliaries, titanium tetrakis(2-pro-panolate) as a catalyst and tert-butyl hydroperoxide (= TBHP, Bu OOH) as the oxidant. If the reaction mixture is kept absolutely dry, catalytic amounts of the dialkyl tartrate-titanium(IV) complex are suflicient, which largely facilitates work-up procedures (Y. Gao, 1987). Depending on the tartrate enantiomer used, either one of the 2,3-epoxy alcohols may be obtained with high enantioselectivity. The titanium probably binds to the diol grouping of one tartrate molecule and to the hydroxy groups of the bulky hydroperoxide and of the allylic alcohol... 

Simple esters cannot be allylated with allyl acetates, but the Schiff base 109 derived from o -amino acid esters such as glycine or alanine is allylated with allyl acetate. In this way. the o-allyl-a-amino acid 110 can be prepared after hydrolysis[34]. The Q-allyl-o-aminophosphonate 112 is prepared by allylation of the Schiff base 111 of diethyl aminomethylphosphonates. [35,36]. Asymmetric synthesis in this reaction using the (+ )-A, jV-dicyclohex-ylsulfamoylisobornyl alcohol ester of glycine and DIOP as a chiral ligand achieved 99% ec[72]. 

Allylic phosphates are used for carbonylation in the presence of amines under pressure. Carbonylation of diethyl neryl phosphate (389) affords ethyl homonerate (390), maintaining the geometric integrity of the double bond[244]. The carbonylation of allyl phosphate in the presence of the imine 392 affords the /3-lactam 393. The reaction may be explained by the formation of the ketene 391 from the acyl phosphate, and its stereoselective (2 + 2] cycloaddition to the imine 392 to give the /3-lactam 393(247],... 

Peroxides. These are formed by aerial oxidation or by autoxidation of a wide range of organic compounds, including diethyl ether, allyl ethyl ether, allyl phenyl ether, dibenzyl ether, benzyl butyl ether, n-butyl ether, iso-butyl ether, r-butyl ether, dioxane, tetrahydrofuran, olefins, and aromatic and saturated aliphatic hydrocarbons. They accumulate during distillation and can detonate violently on evaporation or distillation when their concentration becomes high. If peroxides are likely to be present materials should be tested for peroxides before distillation (for tests see entry under "Ethers", in Chapter 2). Also, distillation should be discontinued when at least one quarter of the residue is left in the distilling flask. 

The Sharpless-Katsuki asymmetric epoxidation reaction (most commonly referred by the discovering scientists as the AE reaction) is an efficient and highly selective method for the preparation of a wide variety of chiral epoxy alcohols. The AE reaction is comprised of four key components the substrate allylic alcohol, the titanium isopropoxide precatalyst, the chiral ligand diethyl tartrate, and the terminal oxidant tert-butyl hydroperoxide. The reaction protocol is straightforward and does not require any special handling techniques. The only requirement is that the reacting olefin contains an allylic alcohol. 

In 1980, Katsuki and Sharpless communicated that the epoxidation of a variety of allylic alcohols was achieved in exceptionally high enantioselectivity with a catalyst derived from titanium(IV) isopropoxide and chiral diethyl tartrate. This seminal contribution described an asymmetric catalytic system that not only provided the product epoxide in remarkable enantioselectivity, but showed the immediate generality of the reaction by examining 5 of the 8 possible substitution patterns of allylic alcohols all of which were epoxidized in >90% ee. Shortly thereafter. Sharpless and others began to illustrate the... 

A number of reaction variables or parameters have been examined. Catalyst solutions should not be prepared and stored since the resting catalyst is not stable to long term storage. However, the catalyst solution must be aged prior to the addition of allylic alcohol or TBHP. Diethyl tartrate and diisopropyl tartrate are the ligands of choice for most allylic alcohols. TBHP and cumene hydroperoxide are the most commonly used terminal oxidant and are both extremely effective. Methylene chloride is the solvent of choice and Ti(i-OPr)4 is the titanium precatalyst of choice. Titanium (IV) t-butoxide is recommended for those reactions in which the product epoxide is particularly sensitive to ring opening from alkoxide nucleophiles. ... 

The asymmetric epoxidation of an allylic alcohol 1 to yield a 2,3-epoxy alcohol 2 with high enantiomeric excess, has been developed by Sharpless and Katsuki. This enantioselective reaction is carried out in the presence of tetraisopropoxyti-tanium and an enantiomerically pure dialkyl tartrate—e.g. (-1-)- or (-)-diethyl tartrate (DET)—using tcrt-butyl hydroperoxide as the oxidizing agent. 

With this epoxidation procedure it is possible to convert the achiral starting material—i.e. the allylic alcohol—with the aim of a chiral reagent, into a chiral, non-racemic product in many cases an enantiomerically highly-enriched product is obtained. The desired enantiomer of the product epoxy alcohol can be obtained by using either the (-1-)- or (-)- enantiomer of diethyl tartrate as chiral auxiliary ... 

Preparation of the aldehyde required for the synthesis of cyclothiazide (182) starts by carbonation of the Grignard reagent obtained from the Diels-Alder adduct (186) from allyl bromide and cyclopentadiene.The resulting acid (187) is then converted to the aldehyde (189) by reduction of the corresponding diethyl amide (188) with a metal hydride. 

Preparation of Diethyl Allyl (1-Methyl-2-Pentynyl) Malonate A solution of 12.1 g of sodium in 182 ml of absolute ethanol was prepared, and thereto were added 126.6 g of diethyl (1-methyl-2-pentynyl) malonate. Most of the ethanol was then distilled off under reduced pressure, and the residue was cooled and 63.5 g of allyl bromide were slowly added thereto. After completion of the addition, the mixture was refluxed for about 1 hour. 

The reaction mixture was cooled, treated with about 100 ml of water, and the oily organic layer which formed was removed, washed with water and dried over anhydrous magnesium sulfate. The dried oily organic material was fractionally distilled in vacuo, and diethyl allyl (1-methyl-2-pentynyl) malonate boiling at 105° to 107°C at the pressure of 1 mm of mercury was recovered. 

Preparation of 1-Methyl-5-Allyl-5-( 1-Methyl-2-Pentynyl) Barbituric Acid A solution of 23.8 g of sodium in 360 ml of absolute alcohol was prepared and thereto were added 38.3 g of methyl urea and 96.8 g of diethyl allyl (1-methyl-2-pentynyl) malonate. The mixture was refluxed for about 20 hours, cooled, and the ethanol was removed by distillation in vacuo. The residue was dissolved in about 300 ml of water and the aqueous solution was washed with ether, and the washings were discarded. The aqueous solution was then acidified with acetic acid, and extracted with three 150 ml of portions of ether. 

In 450 cc of methanol is added 47 grams of sodium metal and the mixture allowed to completely react to form a methanol solution of sodium methoxide. The methanol solution of sodium methoxide is then cooled to 60°C and 68 grams of thiourea which has been thoroughly dried is added with stirring until a uniform solution is formed. Thereafter, 157 grams of diethyl allyl-(1-methylbutyl)malonate is added to the solution of the sodio derivative of thiourea at a temperature of 55°C and the condensation reaction mixture maintained at the said temperature for 24 hours. Methyl alcohol is removed under vacuum during the course of the reaction while maintaining a temperature of 55°C. 

The synthesis of the right-wing sector, compound 4, commences with the prochiral diol 26 (see Scheme 4). The latter substance is known and can be conveniently prepared in two steps from diethyl malonate via C-allylation, followed by reduction of the two ethoxy-carbonyl functions. Exposure of 26 to benzaldehyde and a catalytic amount of camphorsulfonic acid (CSA) under dehydrating conditions accomplishes the simultaneous protection of both hydroxyl groups in the form of a benzylidene acetal (see intermediate 32, Scheme 4). Interestingly, when benzylidene acetal 32 is treated with lithium aluminum hydride and aluminum trichloride (1 4) in ether at 25 °C, a Lewis acid induced reduction takes place to give... 

In light of the previous discussions, it would be instructive to compare the behavior of enantiomerically pure allylic alcohol 12 in epoxidation reactions without and with the asymmetric titanium-tartrate catalyst (see Scheme 2). When 12 is exposed to the combined action of titanium tetraisopropoxide and tert-butyl hydroperoxide in the absence of the enantiomerically pure tartrate ligand, a 2.3 1 mixture of a- and /(-epoxy alcohol diastereoisomers is produced in favor of a-13. This ratio reflects the inherent diasteieo-facial preference of 12 (substrate-control) for a-attack. In a different experiment, it was found that SAE of achiral allylic alcohol 15 with the (+)-diethyl tartrate [(+)-DET] ligand produces a 99 1 mixture of /(- and a-epoxy alcohol enantiomers in favor of / -16 (98% ee). 

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