Skatteboel, L.’s team published research in Tetrahedron in 21 | CAS: 594-81-0

Skatteboel, L. published the artcileReactions of tertiary acetylenic halides with Grignard reagents. Preparation of cumulenes, Computed Properties of 594-81-0, the publication is Tetrahedron (1965), 21(6), 1357-67, database is CAplus.

Me₂C(OH)CCCCMe (0.25 mole), 0.25 ml. CaCl₂, and a small amount of hydroquinone in 104 ml. concentrated HCl mechanically shaken 3.5 hrs. yielded 90% Me₂CClCCCCMe (I), b₁₀ 64-9°, n²⁰_D 1.5116. I (14.8 g.) in 15 ml. dry Et₂O added dropwise in 1 hr. to 170 ml. MeMgBr (0.70M) with stirring at 20°, the mixture stirred 16 hrs. and refluxed 1 hr. with collection of evolved gases trapped at -78° over H₂O, the mixture hydrolyzed with dilute aqueous HCl and the isolated product distilled gave 6.1 g. liquid, b₁₂ 50-2°, n²⁶_D 1.4998. The residue yielded 4.1 g. crystalline compound, purified by chromatography and recrystallization from MeOH to give [MeC CCCCMe₂]₂ (II), m. 140°. as chromatography of the liquid showed the presence of 64, 27, and 9% of 3 compounds (III, IV, V), separated by preparative gas chromatography. On the basis of analysis, spectroscopic data, and identity with a compound prepared by reduction of I with Zn in alc. III was shown to be Me₂C:C:CHC CMe, b₁₃ 50°, n²⁵_D 1.5023. Repeated preparative gas chromatography gave a liquid, n²⁵_D 1.4792, recrystallized at low temperature from C₅H₁₂ to give IV, Me₂CHCCCCMe, m. 27°. I (5 g.) in 30 ml. dry MeOH containing 1.5 g. Na kept 2 hrs. at 20° and refluxed 15 min., treated with H₂O and extracted with C₅H₁₂ yielded 53% V, H₂C:CMeCCCCMe, b₁₃ 53°, n²⁵_D 1.5402, extremely unstable except at low temperature under N. In one experiment the reaction mixture from the Grignard reaction was decomposed with D₂O and the compounds separated Both II and V were unchanged but the product from III, ν 2225 cm.^-1, N.M.R. lacking the band at 4.99 due to the allenic proton, was III-4-d. The new IV lacked the ir band at 1320 cm.^-1 and it was evident that D was actually incorporated at the tertiary C atom of the Me₂CH group. The gas evolved in the reaction analyzed by gas chromatography consisted of 99.9% C₂H₆ with traces of CH₄. Use of EtMgBr gave 61% C₂H₆, 39% H₂C:CH₂, with traces of CH₄. Although no cumulene was formed, the isolation of III showed that rearrangement had occurred and the reaction of Grignard reagents with tertiary acetylenic dihalides was studied. Me₂CClCCCClMe₂ (VI) (5.4 g.) in 15 ml. dry Et₂O added dropwise in 30 min. to 50 ml. MeMgBr (1.54M) with stirring at 20° and the mixture stirred 1 hr., refluxed 1 hr., and hydrolyzed with dilute HCl (all operations under N) yielded 92% Me₂C:C:C:CMe₂ (VII), m. 40°. The gas evolved was 99.9% C₂H₆, but with EtMgBr consisted of 51:49 C₂H₆-H₂C:CH₂. VII was also produced by treatment of VI with Zn. VII was extremely sensitive to O with formation of a polymeric peroxide, isolated by extraction with hot CH₂Cl₂ to CHCl₃ to give crystalline material, C₈H₁₂O₂, m. 112-13° ozonized in CCl₄ followed by treatment with Zn and H₂O to give Me₂CO. Me₂CCl(C:C)₂CClMe₂ (VIII) (10.1 g.) in 15 ml. dry Et₂O added dropwise in 1 hr. to 80 ml. MeMgBr (1.5M) with stirring at 20°, the mixture kept 1 hr. at 20° and decomposed with dilute HCl, the Et₂O solution separated and dried gave ir spectrum, ν 2002 1625 cm.^-1, and uv maximum 215, 228, 308, 321 mμ. Any attempt to isolate the cumulene gave highly unstable polymeric material, explosive at 70-80°, ν 1140 cm.^-1, and containing considerably less O than the above peroxide. On the basis of the assembled data the cumulene structure, Me₂C:C:C:C:C:CMe₂ was assigned to the compound In the reaction of both VI and VIII dehalogenation had occurred and it was shown that the vicinal dihalide, Me₂CBrCBrMe₂ (IX) readily reacted with MeMgBr to yield Me₂C:CMe₂ (X) as the sole isolable product. Production of C₂H₆ from reactions with MeMgBr suggested that the dehalogenation reaction with IX to give the volatile X might be useful as a way of dimerizing Grignard reagent radicals. MeMgBr (140 ml., 1.4M) in Et₂O added dropwise in 2 hrs. to 19.5 g. IX in 25 ml. dry Et₂O and the mixture refluxed 1 hr., cooled, and hydrolyzed with dilute HCl and the washed and dried Et₂O layer fractionated yielded 76% X, b. 70-2°, n²⁰_D 1.4101. The evolved gases contained 99.9% C₂H₆. Similar reaction of IX with EtMgBr gave X and evolved 52% C₂H₆, 48% H₂C:CH₂, and traces of CH₄. Reaction of IX with PhMgBr gave only X and 71% Ph₂, m. 69-70°. PhCCH (5.1 g.) in 20 ml. dry Et₂O treated with 34 ml. 1.48M MeMgBr and the mixture refluxed 6 hrs., the mixture worked up as usual and the Et₂O distilled under reduced pressure, the residue recrystallized from MeOH to yield 63% PhCCCPh, m. 87-8°, and the Et₂O distillate analyzed by gas chromatography showed the presence of 62% X and PhCCH. Distillation of the distillate recovered 1.4 g. PhCCH. The formation of the allene and cumulenes was rationalized by a functional exchange-elimination mechanism involving radicals.

Tetrahedron published new progress about 594-81-0. 594-81-0 belongs to bromides-buliding-blocks, auxiliary class Bromide,Aliphatic hydrocarbon chain, name is 2,3-Dibromo-2,3-dimethylbutane, and the molecular formula is C8H11NO, Computed Properties of 594-81-0.

Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary