Ethylene derivatives 2,3-dimethyl-2-butene

Dihydrothiophene 1,1-dioxide treated with ozone in abs. ethanol and methylene chloride wtih Dry Ice-methanol cooling and stirring until the soln. becomes blue, treated portionwise with liq. SOg during 10-15 sec., and after 2 min. allowed to warm to room temp, during 8-16 hrs. cis- and trfl -2,6-diethoxy-l,4-oxa-thiane 4,4-dioxide (Y 74-81%) mixed with NH4CI and glacial acetic acid, placed in an oil bath preheated to 125-130°, stirred and refluxed 25-35 min. 4H-1,4-thiazine 1,1-dioxide (Y 69-83%). - By the above ozonolysis process, acetals can be obtained from ethylene derivs. E l-Chloro-4-(o-nitrophenyl)-2-butene and methanol -> o-nitrophenylacetaldehyde dimethyl acetal. Y 84%. F. e. s. W. E. Noland and R. D. DeMaster, Org. Synth. 52, 135 (1972). 

The aminocyclopropane derivative 374 and the propellane 372 were obtained, each in 26 % yield, by photocycloaddition of 370 and ethylene in acetone . Diradicals 371 and 373 were suggested as intermediates in the photoreaction (equation 90). The use of isobutene or 2,3-dimethyl-2-butene instead of ethylene gave no cyclopropane product . 

Likewise, the organic products of the reaction between Ta(CHCMe3)Cl3L2 (L = py, THF) and ethylene issue from )5-hydrogen transfer (4,4-dimethylpentene) but also contain the metathesis product 3,3-dimethyl-l-butene. Unlike phosphine derivatives, these latter complexes react with cis-2-pentene to give exclusively the metathesis olefins and act as catalysts for the metathesis of cis-2-pentene. Thus, the presence of a hard ligand and the formation of an intermediate a,a jS-trisubstituted metallacyclobutane complex do not favor jS-hydrogen transfer ... 

Pf-DAB = l,4-diisopropyl-l,4-diazabutadiene) with Ag[OTf] leads to the stable 16-electron derivative [RuGp /i (A,A)-Pf-DAB ][OTf] which reacts with a variety of neutral ligands affording [RuGp(L) /i (A,iV)-Pf-DAB ][OTf] (L = GO, py, PPh3, ethylene, propene, 2-methylpropene, 2-butene, dimethyl maleate, dimethyl... 

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