The Reformatsky Reaction. I. Zinc and Ethyl α-Bromoisobutyrate*

thesulfonate ester, m.p. 37.5-39.5'. After 1 hr. a t this temperature, the mixture was processed as described above under part A. The sulfonate ester was essentially completely consumed. Product analysis for the aleohols was performed on the TCEP column at about 150", and the components were identified by their characteristic retention times. The absolute yield, determined as described above, of total alcohols was 36y0, and consisted of the following proportions of individual components: 22% of V, 47" of VI , 12% of IX, 37% of II,2Y0 of 111, 8% of X and/or XI, and 16% of three unidentified components. The olefin fraction was analyzed on Carbowax at about 90" and consisted of a single product (40y0 yield), namely the diene VI1 which was identified by its retention time. D. Formolysis of cis-2-(A3-Buteny1)cyclohexyl p-Nitroben2enesulfonate.-To a stirred solution of 0.025 ml. of pyridine in 7.5 ml. of anhydrous formic acid at 50 =k 2" was added 51 mg. of the sulfonate ester, m.p. 54-56". After 1 hr. the product was processed as described above in section A. The reaction was essentially complete. The alcohols were analyzed as described above, section C, and the absolute yield of total alcohols was 31 yo, consisting of the following proportions of individual components: 86% of V, 4% of Ix, 770 of 11, and 270 of x and/or XI . Analysis for olefins on a Carbowax column a t ca. 80' showed a single peak corresponding to a 64y0 yield of the diene VII. The identity of these products was based on retention time data. E. Formolysis of Aa-Butenylcyclopentylcarbinyl p-Nitroben2enesulfonate.-A solution of 49 mg. of the sulfonate ester, m.p. 35-37', and 0.025 ml. of pyridine in-7.5 ml. of anhydrous form% acid was heated for 1 hr. a t 50 i 2". The mixture was processed as described above, section A. Analysis of the alcohol fraction as described above, section C, showed the following relative proportions of products: 670 of V, 227, of VI , 3% of I x , 18% of 11, a trace of X and/or XI , and 50y0 of an unidentified alcohol which was not one of the 2-decalols. The identities of these components were established by peak-enhancement experiments. The hydrocarbon fraction was not examined. Treatment of 1-( A3-Buteny1)cyclohexene (VII) with Formic Acid.-A solution of 286 mg. of the diene3 and 0.025 ml. of pyridine in 16 mi. of anhydrous formic acid was heated to 75" for 11.5 hr. under a nitrogen atmosphere. The product was processed and analyzed as for a solvolysis reaction (see description above under section A of the formolysis studies). Analysis of the alcohols on the Craig column indicated a total yield of 42% consisting of the following components in the specified proportions: 5% of V, 15y0 of an unidentified alcohol, 20% of a second unidentified alcohol, and 50% of XI . The remaining 10% was accounted for as six minor peaks in the gas chromatogram. Detectable amounts of trans-2-decalols were not observed. Analysis for olefins on the Carbowax column indicated a total yield of 19%. About 50YG of this fraction corresponded to starting material, and the remainder was accounted for as four peaks in the gas chromatogram. The alcohols were separated by preparative gas chromatography on the PEGS column and examined by infrared methods. The unidentified alcohols corresponded with those obtained previously in the sulfuric-acetic acid cyclization.' Compound XI was obtained as a crystalline solid, m.p. 96-101' (lit."m.p. 104"). When a shorter reaction time (3.5 hr.) was used, the area under the peak corresponding to the tertiary carbinol V increased while that of the other alcohol peaks decreased. The absolute yield of decalol XI was 775. Treatment of 1-(A3-Butenyl)cyclohexanol ( V ) with Formic Acid.-A solution of 341 mg. of the carbinola and 0.025 ml. of pyridine in 15 ml. of anhydrous formic acid was heated for 21 hr. a t 75". The mixture was processed and the product was analyzed as in the preceding experiment. The gas chromatographic pattern for the alcohols was very similar to that obtained in the preceding experiment. About 50y0 of the alcohol mixture corresponded to the decalol XI , and the absolute yield of this material was 25%. The major alcohols were identified by preparative gas chromatographic separation and infrared spectral examination.