2- methyl-1-chloro-1-propene, addition

When isobutylene and chlorine are allowed to react in the dark at 0° in the absence of peroxides, the principal product is not the addition product but methallyl chloride (3-chloro-2-methyl-I-propene). Bubbling oxygen through the reaction mixture produces no change. 

The solution is cooled in an ice bath and is stirred rapidly as 9.65 g (0.107 mole) of l-chloro-2-methyl-l-propene (isobutenyl chloride) [Aldrich] is added over a period of 5 min. The reaction can be followed by observing the changes in the IR spectrum of the solution. The carbonyl absorption bands characteristic of the anion are replaced by those typical of the product at 1998 and 1950 cm. Upon completion of the addition of l-chloro-2-methyl-l-propene, stirring at 0" is continued for 1 hr to ensure completion of the reaction. The resulting solution of dicarbonyl (Ti -cyclopentadienyl)(2-methyl-l-propenyI-KC )iron may be used directly without purification. Alternatively, the product can be isolated and purified by removing solvent under reduced pressure, followed by chromatogra(>Ay of the residue on 300 g of neutral activity III alumina. The column is made up in anhydrous diethyl ether, and after dissolving the crude product in petroleum ether, elution under N2 is carried out with this solvent. The product may 6e further purified by short-path distillation at pressures less than 10 mm (pot temperature less than 40°). It is then sufficiently pure to be stored at -20° for... 

In another paper from the Jackson Laboratories of the du Pont Company (Calcott et al., 34) there is reported a repetition of some of the reactions of Simons and Archer, as well as additional ones. Mono-, di-, and 1,2,4,5 tetraisopropylbenzene were obtained from propylene and benzene both l -chloro-i-butylbenzene and di-(l/-chloro)-d-butylben-zene were obtained from 3-chloro-2-methyl-propene-l and benzene p-f-butyltoluene and di-i-butyltoluene were obtained from diisobutylene and toluene tetraisopropylnaphthalene was obtained from propylene and naphthalene naphthyl-stearic acid was obtained from oleic acid and naphthalene mixed isopropyltetrahydronaphthalene was obtained from propylene and tetrahydronaphthalene 2,4,6-triisopropylphenol was obtained from propylene and phenol a mixture of monoisopropylated m-cresols was obtained from propylene and wi-cresol and di-(s-hexyl)-diphenyl oxide was obtained from hexene-3 and diphenyl oxide. 

Elimination followed by nucleophilic addition to a strained C-C double bond was the main reaction sequence observed when a 1 3 mixture of (2-bromo-5-methyltetracy-clo[3.2.0.0 . 0 ]hept-l-yl)methanol and (7-bromo-5-methyltetracyclo[3.2.0.0 .0 ]hept-l-yl)methanol was allowed to react with a large excess of lithium aziridide. The main product, identified as 2-(aziridin-l-yl)-5-methyltetracyclo[3.2.0.0 -. 0" ]hept-l-yl methanol (13) and isolated in 21% yield, most likely results from aziridide attack on the intermediate lithium 5-methyltetracyclo[3.2.0.0 .0" ]hept-2(7)-en-l-yl)methoxide at C2. ° The other main product, 3-(aziridin-l-yl)-l-methyl-4-oxatetracyclo[4.3.0.0 .0 ]nonane (14), which was isolated in 15% yield, conceivably originates from the same intermediate as outlined above. Acyclo-propene intermediate was probably also formed when l-chloro-5-methyl-exo-6-phenyl-3-oxabicyclo[3.1.0]hex-2-one reacted with lithium 2,2,6,6-tetramethylpiperidide (LTMP) and gave 5-methyl-e.vo-6-phenyl-l-(2,2,6,6-tetramethyl-l-piperidyl)-3-oxabicyclo[3.1.0]hex-2-one (15) in 66% yield. 

Scheme 23 also outlines a potential problem with the syjnthesis. The initial attack can occur at either end of the double bond of the 7r-complex, 28, to give the two isomers 29 and 30 in a ratio of 4 1. These two isomers are expected from Wacker chemistry since propene produces both acetone and propanal in about the same ratio from the two modes of addition. However, as shall be discussed below, this is not a serious problem with most a-olefins. The same catalyst oxidizes methyl vinylketone only to 4-chloro-3-hydroxy-2-butanone (29 R = C(=0)CH3). The optical purity was still only about 12%. 

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