Methylene bis-dicarbonyl

Interestingly, they were able to perform this transformation sequentially starting from a large excess of N,N-dimethylaniline (10 equiv.) and the ketoester 10-A under standard conditions this reaction was stopped at the formation of the oxidative coupling adduct 10-B which could be obtained in 47% yield (together with 37% of 10-C). The reaction of 1 equiv. of 10-B with one extra equivalent of 10-A led to the methylene bis-dicarbonyl compound 10-C in 91% yield, indicating that 10-B can be an intermediate of the reaction (Scheme 4.10). 

Scheme 4.10 Proposed pathway to obtaining methylene bis-dicarbonyl compounds.

In a related reaction, condensation of 1,3-dicarbonyl compounds (323) with methylene bis-imidazolidine (324) gave substituted imidazo[l,2-a]pyridines (325) (78LA1491). The reactions of aldehydes (326) with ethyl 2-imidazolidinyleneacetate (327), or those of aldehydes (326) and jS-dicarbonyl compounds with imidazolidines (330) gave similar structures (328) and (331) (78LA1476, 73GEP2210633). 

Tetrachloro-l, 3-dithietane forms a bis adduct with mercury (I) nitrate,whose structure was investigated by IR and Raman spectra. A cyclo-pentadienyl manganese(0) dicarbonyl complex of the dimer of 2,3-diphenylcyclo propenethione has been reported. Raney nickel desulfurizes the tetraester 538 and the desulfurization of the questionable dithietanes obtained by dimerization of thiofluorenone and thiobenzophenone give, respectively, bis-fluorenylidene and tetraphenylethylene. The electrochemical oxidation of 1,3-dithietane has been investigated. 2,2 -[Oxybis(methylene)]bis-l,3-dithietane is inert to boron trifluoride etherate after 30 days at room temperature. ... 

The competition between Michael addition of a,(3-unsaturated ketones and Diels-Alder reactions involving furan and 2-methylfuran is affected by the catalyst used. Methyl vinyl ketone gives the alkylation product with furan and 2-methylfuran in the presence of silica gel (88TL175). Bis(alkylated) products have also been obtained in reactions of 2-methylene-1,3-dicarbonyl compounds (90H(31)1699). An intramolecular proton catalyzed alkylation reaction of an a,(3-unsaturated ketone provided a straightforward synthesis of norpinguisone (90TL4343) and in the example shown in Equation (4) the cyclization reaction involved an a,(3-y,8-dienone (94TL4887). 

Bis(methylene)butanedioate 68, which is an interesting derivative of butadiene as well as acrylate, can be prepared by the dicarbonylation of the dicarbonate of butynediol 64 [16]. The monocarbonylation of 64 affords the allylic carbonate 65, and the diester 68 is obtained by further carbonylation of n- or cr-allyl complexes 66 and 67. 

Dicarbonyl compounds, such as malonate derivatives, can also be classified under two categories. As well as reacting simply as a three-atom bis-electrophilic fragment (as in the synthesis of barbiturate 10.25 (page 77), an alternative reactivity is available. Condensation (by nucleophilic attack) of the active methylene carbon and electrophilic reaction at just one of the carbonyl groups is a two-atom nucleophilic/electrophilic profile, as seen in the preparation of coumarin 9.16. 

In a very similar manner, tandem 1,6- and 1,4-additions of -dicarbonyl compounds to methyl 2,4-pentadienoate were utilized by Danishefsky and coworkers- foi the formation of several bi- and tricyclic ring systems. For example, reaction of the enolate of dimedone with this ester gave the expected 1,6-addition product protonation/deprotonation set the stage for a subsequent intramolecular 1,4-addition (equation 9). Likewise, a ketodiester was used to transform the pentadienoate in a one-pot procedure by consecutive 1,6- and 1,4-additions into a richly functionalized tricyclic product which was then converted into the natural product ( )-cpiclovane (equation 10). According to this principle, Irie and coworkers obtained several decalin-2,7-diones by treatment of 2-methylen-2-cyclohexenones with dimethyl 3-oxoglutarate. 

A similar dramatic influence of ionic liquid was also reported by Ranu s group in the Michael reaction of active methylene compounds with methyl vinyl ketone and methyl acrylate in the presence of an ionic liquid, 1-butyl-3-methylimidazolium hydroxide ([bmImjOH). Interestingly, open-chain 1,3-dicarbonyl compounds reacted with methyl vinyl ketone and chalcone to give the usual monoaddition products, whereas the same reactions with methyl acrylate or acrylonitrile provided exclusively bis-addition products (Scheme 5.55). 

Aldol condensation between a 1,3-dicarbonyl component and a ketone with an a-methylene, under acidic, dehydrating conditions, prodnces pyrylinm salts.It is likely that the initial condensation is followed by a dehydration before the cyclic hemiacetal formation and loss of a second water molecule. The use of the bis-acetal of malondialdehyde, as a synthon for malondialdehyde, is one of the few ways available for preparing a-unsubstitnted pyrylinms. ... 

Als Enol-ether von 1,3-Dicarbonyl-Verbindungen und 3-Oxo-alkansaure-estern reagieren 5-Aryl-2-(ethoxycarbonyl-methylen)-4-methyl-3-oxo-2,3-dihydro-furane mil 70%iger Hy-drazin-Hydrat-Losung zu 3(5),3 (5 )-Bi-lH-pyrazolylen988. 

Acrylnitril-dicarbonyl-11.3.5-trimethyl-benzol)- 1418 Acrylnitril-pentacarbonyl- 1418 Athylen-benzol-dicarbonyl- 141.8 Athylen-dicarbonyl-(t.3,5-trimelhyl-benzol)- 1418 Bcnzocyclohuladicn-tetracarbonyl- 1422 Benzol-carbonyl-cycloocten-nitroso- 1419 Benzol-dicarbonyl-(diphenyl-acctylen)- 1418 Benzol-dicarbonyl-maleinsaurcanhydrid- 1418 (Bis-[methylen]-hvdraz.in)-tetracarbonyl- 1422 Cyclohcpten-dicarbonyl-(hexamethyl-benzol)- 1419 Cyclopentadien-[bmadien-(l,3)]-dicarbonyl- 1419 Cyelopenten-dicarbonyl-(l,3.5-trimethyl-bcnzoll-... 

The Knoevenagel condensation with 1,3-dicarbonyls followed by a Michael reaction of a second molecule of the methylene compound, with or without addition of an amine or ammonia, may be used for the qualitative and quantitative determination of aldehydes even in the presence of ketones. Thus, cyclic 3-diketones such as dimedone (59) react with aldehydes but not with ketones in the absence of a catalyst. For the characterization the bis(2,6-dioxo-4,4-dimethylcyclohexyl)methanes (67) or the 4,6-dioxo-2,2,8,8-tetramethyl-1,2,3,4,5,6,7,8-octahydro-SW-xanthene (68) may be used.93,104,105... 

Butyne-l,4-diol derivatives undergo dicarbonylation of different types. A simple synthetic method of bis(methylene)succinate 78 is the carbonylation of the dicarbonate of but-2-yne-l,4-diol (77) at 50°C [20]. 

C2 6H2 2C02Mn04P, Dicarbonyl-cyclopentadienyl-manganese-M3 (benzyl-phosphido)-bis(carbonyl-cyclopentadienyl-cobalt), 45B, 980 C26H25F12N3P2V2, Bis(fulvalene)bis(acetonitrile)divanadiumUII)(V-V) bis(hexafluorophosphate) acetonitrile, 45B, 980 C2 6H2 sN2Ti, 4-Methylene-3,7,8-trimethyl-1,10-phenanthrolinebis( t -cyclopentadienyl)titanium, 46B, 902 C2 6H2 sNijTi 2, M-Pyrazole-bis(Ty -cyclopentadienyl)titanium(III), 44B, 770... 

Visible light photocatalysis has likewise been exploited for the preparation of methylene-bridged bis(l,3-dicarbonyls) by reaction of 2,3-dicarbonyl and AT,iV-dimethylbenzylamine7 ... 

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