2876-53-1

The alkylation of aryl sulfamates and carbamates using iron catalysis is reported. The method constructs sp2-sp3 carbon-carbon bonds and provides synthetically useful yields across a range of substrates (>35 examples). The directing group ability of sulfamates and carbamates, accompanied by their low reactivity toward conventional cross-couplings, renders these substrates useful for the synthesis of polyfunctionalized arenes.

The use of mixtures of metallic lithium and sodium in the naphthalene-alkali metal systems in THF leads to a synergistic acceleration of the naphthalene alkylation with ethene at room temperature and atmospheric pressure. The greatest synergistic effect is observed at a Li:Na molar ratio of 2:1. Under these conditions, the overall conversion of naphthalene into alkylation products (linear 1-alkylnaphthalenes and their dihydro derivatives) attains 88% after 24 h (a (Li + Na):C10H8 ratio is 2:1). The use of mixtures of metallic lithium and potassium in such systems results, however, in a synergistic retardation of the alkylation process. The strongest retarding effect is observed at a Li:K molar ratio of 1:1. The efficiency of the toluene alkylation with ethene in the naphthalene-alkali metal systems in THF is also increased on the replacement of lithium or sodium by their mixtures. The best results are obtained at a Li:Na molar ratio of 1:3. With this Li:Na ratio, toluene is almost quantitatively converted into linear and α-branched higher monoalkylbenzenes (24 h, (Li + Na):C10H8 = 2:1). The rate of the naphthalene alkylation with ethene in the presence of toluene is enhanced as well on an introduction of mixtures of lithium and sodium into the system. However the maximum of the activity is shifted here towards higher lithium content (Li:Na = 1:1). A similar synergistic effect of lithium and sodium was found on studying the toluene alkylation with ethene in the phenanthrene-Li-Na systems in THF (a (Li + Na):phenanthrene ratio is 3:1). An addition of potassium to sodium also considerably increases the efficiency of the toluene and naphthalene alkylation with ethene in the naphthalene-based systems. The possible mechanism of the alkali metal synergism in the above-mentioned alkylation reactions is discussed.

Systems based on naphthalene and alkali metals (Li, Na, K) in THF are able to induce the alkylation of naphthalene with ethene at room temperature and atmospheric pressure. The highest activity in this reaction is exhibited by the naphthalene-potassium system which converts naphthalene into 1-ethylnaphthalene (1) and small amounts of two isomeric dihydro derivatives of 1 in a yield of 85% (24 h, K:C10H8 = 2:1). The same alkylation products are formed when metallic sodium is used instead of potassium. The interaction of ethene with the naphthalene-lithium system (24 h, Li:C10H8 = 2:1) affords 1 together with 1-n-butylnaphthalene (4), 1-n-hexylnaphthalene (5), 1-n-oktylnaphthalene (6) and dihydro derivatives of 5 and 6 in a total yield of 60%. Alkylation of toluene with ethene in the naphthalene-alkali metal systems leads to the formation of higher monoalkylbenzenes. The greatest toluene conversion (48%, 24 h) is observed on using the lithium-containing system (Li:C10H8 = 2:1), in the presence of which a mixture of n-propylbenzene (11), n-pentylbenzene (12), 3-phenylpentane (13) and 3-phenylheptane (14) is produced from ethene and toluene. On the replacement of lithium by sodium or potassium, only 11 and 13 are obtained. A treatment of biphenyl, phenanthrene, trans-stilbene, pyrene and anthracene with alkali metals in THF also gives systems capable of catalyzing the alkylation of toluene with ethene at 22 °C. Of particularly active is the stilbene-lithium system (Li:stilbene = 3:1) which converts toluene into a mixture of 11-14, n-heptylbenzene and 5-phenylnonane in a yield of 58%. In all cases, the rate of the alkylation considerably increases in the presence of the solid phase of alkali metal. The mechanism of the reactions found is discussed.

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