1,3,2-dioxaborinane, 2-ethynyl-5,5-dimethyl- 2-ethynyl-5,5-dimethyl-1,3,2-dioxaborinane InChI=1/C7H11BO2/c1-4-8-9-5-7(2,3)6-10-8/h1H,5-6H2,2-3H