Nucleophilic reactions of a 14-vertex closo-carborane are reported. 2,3-(CH2)(3)-2,3-C2B12H12 (1) reacts with MeOH at 70 degrees C to give closo-CB11 anions [1,2-(CH2)(3)CH(OMe)-1-CB11H10](-) ([2a](-)), [1,2-(CH2)(2)CH(OMe)CH2-1-CB11H10] ([2b](-)), and [1,2-(CH2)(2)CH=CH-1-CB11H10](-) ([2c](-)). It is suggested that [2c](-) is an intermediate for the isomerization from [2a](-) to [2b](-). Treatment of 1 with MeOH/Me3N, 'BuOK or LiNMe2 affords nido-C2B12 species [8,9-(CH2)(3)-mu-11,1 2-(Nu)BH-8,9-C2B11H11](-) (Nu = MeO ([3a](-)), (BuO)-Bu-t ([3b](-)), and Me2N ([3c](-))). In the presence of acid such as HCl, anions [3](-) are converted to 1. However, [3](-) undergo deboration reaction, in the presence of bases, to generate a nido-C2B11 anion [8,9-(CH2)3-8,9-C2B11H12](-) ([4]) that can also be formed directly from the reaction of 1 with excess CsF or piperidine. Mechanistic studies show that [3a]- is the first intermediate in the reaction of 1 with MeOH and [4](-) is unlikely an intermediate.