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

We report an improved synthesis of 1‐halocarba‐closo‐dodecaborate anions 1‐Hal–CB₁₁H and their efficient conversion to the undecamethylated anions 1‐Hal–CB₁₁Me (Hal = Cl, Br, I) and the hexamethylated anions 1‐Hal‐(7–12)‐(CH₃)₆–CB₁₁H (Hal = F, Cl) by treatment with methyl triflate in sulfolane in the presence of calcium hydride to remove the triflic acid byproduct. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:217–223, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20224