Preparation of undecamethylated and hexamethylated 1‐halocarba‐closo‐dodecaborate anions

Chemistry of the Carba-closo-dodecaborate(−) Anion, CB11H12-

“…48 As mentioned in section 8.1, methylation of the 1-fluoro anion 169 stops after six methyl groups have been introduced into positions 7-12. 48 The 1-chloro anion (170) is exceptional in that it is possible to stop the reaction when the introduction of the first six methyls into positions 7-12 is complete, securing a good yield of the hexamethylated anion, and after a much longer time, the undecamethylated anion is formed in high yield.…”

“…48,164 Typical examples of introduction of substituents into the CB 11 H 12 -cage using electrophilic reagents are shown in Schemes 6 and 7. 15 The mechanism of these substitutions has not been studied in detail.…”

“…Reaction of 1 and its derivatives with electrophilic halogenating agents, such as the elemental halogens themselves, follows the general reactivity patterns discussed for alkylation and is even more facile. The nature of the products does not indicate whether the reaction occurred by the electrophilic replacement of Scheme 8 or 22 1, MeBr 72 18 36, A 16 13 2, B 73 18 37, A 16 13 2, A 124 c, 16 1, n-BuLi, C6F5Br 51 14 1, b C7H7 + BF4 128 13 126, A 53 22 1, EtBr 129 13 126, C 54 13 11, C 131 30 130, A 55 13 18, A 204 46 177, D 57 18 38, A 205 46 178, D 58 18 39, A 206 46 179, D 59 18 40, A 208 13 196, A 60 18 41, A 210 13 176, A 61 18 42, A 211 13 209, A 62 18 43, A 214 13 194, A 63 18 27, A 215 13 211, A 64 18 28, A 217 13 199, A 65 18 29, A 218 48 169, A, 6 h 66 18 30, A 219 48 170, A, 6 d 67 18 31, A 220 48 170, A 68 18 32, A 221 48 171, A 69 18 33, A 222 48 172, A 70 18 34, A a A: MeOTf, CaH2, sulfolane. B: MeOTf, 2,6-di-tert-butylpyridine, CaH2.…”

“…What is most needed at present is a high-yield one-step or two-step synthesis from cheap bulk chemicals. As we shall see in section 7, starting with bulk chemicals, at this time some 29 Ph H H I 162 36 Me Me Me OMe 196 13 TIPS H H I 163 36 Me Me Me OH 197 44 Me H Cl Cl 164 21 HS H H H 198 44 Me H Br Br 165 21 MeS H H H 199 14 Me H I I 166 21 Me2S + H H H 200 40 Me F F F 167 21 H H H M e 2S 201 45 Me Cl Cl Cl 168 21 H H H X g 202 41 Me Br Br Br 169 37 F H H H 203 41 Me Me 179 39 H H I I 213 15 Me Me Me F 180 40 H F F F 214 47 Me Me Me I 181 41 H C l C l C l 215 13 Me Me I Me 182 41 H B r B r B r 216 13 Me I Me Me 183 41 H I I I 217 13 Me Me I I 184 41 Br Br Br Br 218 48 F H Me Me 185 42 Me3N + H H I 219 48 Cl H Me Me 186 31 X d H H I 220 48 Cl Me Me Me 187 43 NH3 + H I I 221 48 Br Me Me Me 188 43 NH3 + I I I 222 48 I M e M e M e 189 14 H B r C l C l 223 49 H O H B r B r 190 14 H I Cl Cl 224 16 H H H X h 191 14 H C l B r B r 225 16 H H H X i 192 …”

Improved synthesis of [closo-1-CB9H10]– anion and new C-substituted derivatives

“…This general improvement of the C-substitution reactions was also observed for the [closo-1-CB 11 H 12 -1-X] -halogenated series when CuCl was employed 13 . An alternative iodination procedure using I 2 produced a 4:1 ratio of parent derivative 1 and iodinated derivative 3a by 11 B NMR analysis of the crude reaction mixture 15 .…”