A new route to incompletely condensed silsesquioxanes: acid-mediated cleavage and rearrangement of (c-C6H11)6Si6O9 to C2-[(c-C6H11)6Si6O8X2]
Abstract
Acid-mediated cleavage and rearrangement of (c-C6H11)6Si6O9 1 by triflic acid (TfOH) and methanesulfonic acid (MsOH) produces good yields of C2-[(c-C6H11)6Si6O8X2] (4a, X = OTf; 4b, X = MsO), which reacts with water, LiNMe2 and LiCCPh to afford C2-[(c-C6H11)6Si6O8(OH)2] 5, C2-[(c-C6H11)6Si6O8(NMe2)2] 8 and C2-[(c-C6H11)6Si6O8(CCPh)2] 9; silylation of 5 with ClSiMe2H–Et3N produces C2-[(c-C6H11)6Si6O8(OSiMe2H)2] 6, while reaction of 5 with HBF4·OMe2–BF3·OEt2 produces C2-[(c-C6H11)6Si6O8F2] 7, which also reacts with LiNMe2 and LiCCPh to afford 8 and 9.