O. M. Nefedov

REACTION OF ETHYL DIAZOACETATE WITH 2-ALKENYLFURANS*

Conclusions1.In contrast to alkenylaromatic compounds, 2-alkenylfurans react with ethyl diazoacetate under conditions of catalytic, thermal, and photolytic decomposition of the latter with the addition of the carbethoxycarbene fragment both at the exocyclic double bond and also at the furanyl ring, which in the latter case leads to the formation of esters of triply unsaturated ketoacids with yields up to 58%.2.The reaction direction and the yields of the final products depend on the degree and the character of substitution of the vinyl group and position 5 of the furan ring and not on the method of decomposition of ethyl diazoacetate.3.Satisfactory correlation between the logarithm of the relative rate constant of the reaction of addition at the vinyl group of 5-substituted 2-vinylfurans and the Hammettσ constants is observed upon the thermocatalytic decomposition of EDA. The value of ρ indicates the great sensitivity of the reaction as regards electron effects of the substituents in comparison with styrenes.

Reaction of furan and its derivatives with ethyl diazoacetate in the presence of copper sulfate

The thermocatalytic reaction of ethyl diazoacetate with alkylfurans and the esters of furylcarboxylic acids leads to the formation of the ethyl esters of the corresponding trans, trans 1, 3-alkadien-5-onecarboxylic acids, while reaction with furan leads to the formation of a mixture of a similar ester and 6-ethoxycarbonyl-2-oxabicyclo [3.1. 0]-3-hexene, which is easily isomerized to the former.

Reaction of heteroaromatic compounds with carbenes (review)

The literature data on the reactions of heteroaromatic compounds of various classes with halo-, alkyl-, alkoxy-, and ketocarbenes are examined. The mechanisms of these reactions and the effect of the methods used to generate the carbenes and the nature of the heterocycle on the direction of the reaction and the structures and yields of the final products are discussed. An estimate of the possibilities of the preparative utilization of the indicated reactions is given.

Reaction of phenylchlorocarbene with 2-alkenylfurans and some transformations of the formed adducts

1. 2-Alkenylfurans react with phenylchlorocarbene to give furyl-gem-phenylchlorocyclopropanes. 2. Reduction of the furyl-gem-phenylchlorocyclopropanes with sodium in liquid ammonia leads to hydrogenolysus of the cyclopropane ring with the formation of 1-furyl-3-phenylalkanes. 3. The catalytic hydrogenation of the furyl-gem-phenylchlorocyclopropanes in a flow system over Pt/C at 260–265° leads to hydrogenolysis of both the furan and cyclopropane rings with the formation of phenyl-substituted ketones.

Preparation of aliphatic diketones by hydrogenolysis of difurylalkanes and difurylalkenes

The hydrogenolysis of di-(2-furyl)alkanes or di-(2-furyl)alkenes in the vapor phase over Pt/C is a new and general method for the preparation of aliphatic diketones.

Thermocatalytic transformations of 1, 1-dichlorocyclopropane and 1, 1-dighloro-2-(2-furyl) cyclopropanes

1. l, 1-Dichlorocyclopropane when passed over either Pd/C or Pt/C at ≥ 100° in excess H2 undergoes reductive hydrogenolysis to give propane. 2. The hydrogenolysis of 1, l-dichloro-2-(2-furyl) cyclopropanes over Pd/C at 150–250° leads to the predominant formation of the corresponding 2-n-alkyltetrahydrofurans, and to the corresponding 4-alkanones when. the hydrogenolysis is run at higher temperatures or Pt/C is used as the catalyst.