Diethyl ketomalonate

The formation of the naphthalene (73) from the bis-ylide (72) and diethyl ketomalonate involves an unusual olefin synthesis on the carbonyl of an ester group. The methylene-pyrans (75) were formed when the diethyl malonates (74) were refluxed with j3-keto-ylides in xylene or decalin. Possible intermediates are the ketens (76) and the allenes (77). Addition of ylide to the allenes gives the betaines (78) which form methylene-pyrans either directly or via acetylenes as shown. 

A crystal structure of the C02 derivative of (8), K[Co(salen)( 71-C02)], haso been reported in which the Co—C bond is 1.99 A, the C—O bonds are both equivalent at 1.22 A and the O-C-O angle is 132°.125 Carboxylation of benzylic and allylic chlorides with C02 in THF-HMPA was achieved with (8) electrogenerated by controlled-potential electrolysis,126 in addition to reductive coupling of methyl pyruvate, diethyl ketomalonate and / -tolylcarbodiimide via C—C bond formation. Methyl pyruvate is transformed into diastereomeric tartrates concomitant with oxidation to the divalent Co(salen) and a free-radical mechanism is proposed involving the homolytic cleavage of the Co—C bond. However, reaction with diphenylketene (DPK) suggests an alternative pathway for the reductive coupling of C02-like compounds. 

It has been shown that complete selectivity for the hetero-Diels-Alder cycloadduct 109 (100% endo, 60% ee) can be achieved in the hetero-Diels-Alder reaction of 1,3-cyclohexadiene 108 and ethyl glyoxylate 99 using ent-6 and copper(II) triflate derived catalyst complex. Another interesting reaction introduced by Jprgensen and co-workers was the reaction between 1,3-cyclohexadiene 108 and diethyl ketomalonate 110 to form cycloadduct 111 in 76% yield with an ee of 84% (Fig. 9.35b, p. 558). ... 

Important extensions of proline catalysis in direct aldol reactions were also reported. Pioneering work by List and co-workers demonstrated that hydroxy-acetone (24) effectively serves as a donor substrate to afford anfi-l,2-diol 25 with excellent enantioselectivity (Scheme 11) [24]. The method represents the first catalytic asymmetric synthesis of anf/-l,2-diols and complements the asymmetric dihydroxylation developed by Sharpless and other researchers (described in Chap. 20). Barbas utilized proline to catalyze asymmetric self-aldoli-zation of acetaldehyde [25]. Jorgensen reported the cross aldol reaction of aldehydes and activated ketones like diethyl ketomalonate, in which the aldehyde... 

Zirconacyclopentadienes 18 react with diethyl ketomalonate in the presence of BiCh to afford fully substituted 2H-... 

An hDA reaction of the thermally generated (trialkylsilyl)vinylketene 888 with diethyl ketomalonate furnishes the 5,6-dihydropyran-2-one 889 in excellent yield. Protodesilylation of the cycloadduct 889 is achieved in quantitative yield upon its exposure to methanesulfonic acid (Scheme 244). A photochemical Wolff rearrangement of the silyl diazo compound 890 can also be used to generate an intermediate diene for reaction with diethyl ketomalonate to afford the 5,6-dihydropyran-2-ones 891 (Equation 358) <19990L641>. 

A highly electron-deficient carbon-oxygen double bond can also participate in the co-cyclotrimerization with alkynes under the ruthenium catalysis. The cycloaddition of commercially available diethyl ketomalonate with the diynes 21 proceeded at 90 °C in the presence of 5-10 mol % Cp RuCl(cod). The expected fused 2ff-pyrans 27, however, underwent thermal electrocyclic ringopening to produce cyclopentene derivatives 28 (Eq. 14) [23]. 

Dicarbonyl 39 is quite effective in promoting the reductive coupling of carbonyl or imino functional groups. Addition of diethyl ketomalonate to solutions of 39 yields 43 (116). 

A mixture of diethyl ketomalonate (6.12g) and 1-octadeeene (8.84 g) were stirred and heated to 160-170 °C 3 hours. The temperature was then increased to 200 °C for 30 hours. Upon cooling a solid was obtained which was re-crystallized in diethyl ether and the product isolated. MS and IR data supplied. 

An oligomer containing pendent ethylidene norbornene was also reacted with diethyl ketomalonate as illustrated in Eq. 1 and discussed by the author. 

As shown below, a simple way to construct 3-alkylidenetetrahydrofurans was the Lewis acid promoted reaction between alkylidenecyclopropanes and diethyl ketomalonate <03TL3839>. Wittig reaction of a 3-ketotetrahydrofuran expectedly led to the formation of a 3-vinyltetrahydrofuran <03JOC1150>. 

An alternative to the Bach procedure (BocN3/FeCl2) for the synthesis of Boc-protected sulfimides was developed in 2002 (Scheme 76) [171]. Oxaziri-dine 312, prepared from diethyl ketomalonate, was found to iminate allylic sulfides 309 at low temperatures. The resulting allyl sulfimide (not shown) immediately rearranged to protected amines 313 in high yields. The possibility of preparing a-amino acid derivatives like 314 is a noteworthy feature although the compounds are, of course, racemic. 

Organoaluminum and Sn(IV) Lewis acid-mediated [3 + 2] cycloadditions of oxa-zoles and aldehydes or diethyl ketomalonate have been observed [116]. The reactions are highly regioselective, with stereoselectivity highly dependent upon the Lewis acid used (Eq. 76). For example, the (BINOL)AlMe-promoted reaction between benzal-dehyde and the oxazole furnishes the oxazoline with a transicis ratio of 2 98. The selectivity is reversed with SnCU which results in a transicis ratio of 85 15. trans-5-Sub-stituted 4-alkoxycarbonyl-2-oxazolines are synthesized under thermodynamic conditions in the aldol reaction of isocyanoacetates with aldehydes [117]. 

Although enamines readily undergo intramolecular condensation with ketones (Section VI. D) the only intermolecular reaction we are aware of is that with diethyl ketomalonate . Whereas cyclic ketone enamines gave the aldol product, with enamines of acyclic ketones only the morpholine enamine of pentan-3-one gave the aldol product (73). The more reactive pyrrolidine enamine cyclysed onto the ester group to give the... 

The stereochemical outcome of the hetero Diels-Alder reaction of the erythrose based diene with sodium glyoxylate was further rationalized by preparing the same compounds via decarboxylation of 2-carboethoxy-2-deoxy-2-ulosonic acid esters, obtained by cycloaddition with diethyl ketomalonate [146], A range of 2-nonulosonic acid derivatives - KDN analogues - were prepared including protected form of 2-deoxy-KDN,... 

DIELS-ALDER REACTIONS Benzocyclopropene. 1,2-BisC3-tosyIethoxycarbonyl)-diazene. Cyclobutadiene iron tricarbonyl. 1,2-Dicyanocyclobutene. Diethyl ketomalonate. 1,3,4,6-Heptatetraene. 2-Hydroxy-5-oxo-5,6-dihydro-2/f-pyrone. 3-Hydroxy-2-pyrone. Isopropylidene isopropylidenemalonate. Lithium tetra-methylpiperidide. 4-Methoxy-5-acetoxymethyl-o-benzoquinone. 4-Methoxy-5-methyl-o-benzoquinone. frans-l-Methoxy-3-trimethyl-silyloxy-l,3-butadiene. Per-fluorotetramethylcyclopentadiene. 4-Phenyl-l, 2,4-triazoline-3,5-dione. Potassium f-butoxide. 

UNSATURATED NITRILES Trimethylsilylmethyllithium. aj3-UNSATURATED SULFONES Benzyltriethylammonium chloride. a,(3-UNSATURATED SULFOXIDES Diethyl phosphorylmethyl methyl sulfoxide. (3,7-UNSATURATED-6-VALER0LACT0NES Diethyl ketomalonate. VINYLACETATES Cuprous acetate. 

---