Edward McNelis

Ring expansions of alkynyl cyclopentanols with iodine and Koser's reagent.

Abstract Equimolar amounts of iodine, Kosers reagent, and 1-bromoethynylcyclopentanols with none, one or two methyl groups in the α-position lead to ring expansions in acetonitrile at room temperature in yields of 75 to 85%. In the so-formed 2-[bromoiodomethylidene]cyclohexanones, the (Z) isomer was preferred exclusively in the unsubstituted compound. The Z E ratio was 7.7 for the dimethyl compound and 3.3 for the monomethyl case. The corresponding bromine and Kosers reagent with 1-iodoethynylcyclopentanol afforded a ring expanded product with Z E ratio of 12:1.

α-Haloenones from secondary alkynols

α-Iodoenones and α-bromoenones are formed from secondary alkynols by the use of the appropriate N-halosuccinimide and a catalytic amount of certain Lewis acids. For example, 3-hexyn-2-ol (1) was converted to (Z)-4-iodo-4-hexen-3-one (2) in 85–95% yields with an equimolar quantity of NIS and tenth molar (hydroxy (toxyloxy) iodo) benzene (3) in methanol or 1-methyl-2-pyrrolididone

Phenyl shifts to vinyl cations formed by iodination of alkynes

Abstract Iodine and several of its oxides react with alkynyl alcohols in methanol to afford β-iodo-α,β-unsaturated ketones.

Dichlorotetracarbonyltungsten as a catalyst for olefin metathesis

Abstract The photolysis of hexacarbonyltungsten (I) in carbon tetrachloride yields a catalytic mixture for olefin metathesis. One of the principal products of this transformation is dichlorotetracarbonyltungsten (II). Chemical preparation of II from I and chlorine was carried out. Authentic II was shown to give catalysis of 2-pentene metathesis by either heating in chlorobenzene or chloroform or irradiation in chlorobenzene or carbon tetrachloride. The Dubois report of phosgene formation in the original irradiated mixture of I in carbon tetrachloride was shown to be an artifact.

Formations of mixed β,β-dihaloenals from halogenated secondary alkynols

Abstract Iodine and Kosers reagent have been used in stoichiometric amounts to convert 3-bromo-1-phenylpropynol to (Z)-3-bromo-3-iodo-2-phenylpropenal in high yield. The latter is a major component of reaction mixtures of 3-iodo-1-phenylpropynol and bromine with Kosers reagent.

Ring expansion of an α-bromoalkynol camphor by means of iodine and Koser's reagent

Abstract The bromoethynyl adduct of camphor was treated with equimolar amounts of iodine and Kosers reagent (HTIB) to afford in good yield and in good stereospecificity a (Z)-bromoiodoenone, a synthon for enantiospecific syntheses.

Reactive silica: XVI. Reaction with cyclopropane, benzene, and toluene☆

Abstract Infrared spectroscopy was used to follow the sorptions of relatively stable adsorbates by reactive silica. Dissociative chemisorption occurred in each case. With cyclopropane, the ring was disrupted and at least three distinct surface species were formed. The main surface product resulting from cyclopropane sorption was also formed when propene was adsorbed. Ring disruption also occurred with benzene, leading to the formation of silanols and some coke-like hydrocarbons, but surface aryls were not observed. However, two surface aryl species were formed with toluene.

Facile formations of ketals of α, α-dihaloacetophenones

Abstract Ketals of α,α-dihaloacetophenones are prepared in high yields from phenylethyne and N-halosuccinimide with catalytic quantities of p-toluenesulfonic acid.

Hexacarbonyltungsten and carbon tetrachloride as a photochemical system for olefin metathesis

The irradiation of hexacarbonyltungsten and carbon tetrachloride affords a catalyst for the metatheses of hept-3-ene, pent-2-ene, and E,E-deca-2,8-diene.

Facile Preparation of the Methyl Acetal of Methyl Phenylglyoxylate

Abstract The methyl acetal of methyl phenylglyoxylate has been prepared from halophenylethynes, N-iodosuccinimide and catalytic amounts of (hydroxy(p-tosyloxy)iodo)benzene or p-toluenesulfcnic acid in methanol at room temperature.