Acid-catalyzed reactions of (3-(naphthalen-2-yl)-2,2-bis(trimethylsilyl)oxiran. A new synthesis of functional-group-substituted vinylsilanes

The magnesium bromide-diethyl etherate-catalyzed ring-opening of (3-(naphthalen-2-yl)-2,2-bis(trimethylsilyl)oxiran 2 with thiophenols affords (1-trimethylsilylvinyl)sulfides 3 and the (1-bromovinyl)silane 4. Nucleophilic attack occurs regioselectively at the position α- to silicon. The compound 2 has been converted into the (1-trimethylsilylvinyl)amide 5 with an excess of acetonitrile and into the (1-trimethylsilylvinyl)acetate 6 with acetic acid/acetic anhydride. These reactions proceed with catalytic amounts of boron trifluoride-diethylether. Treatment of 2 with acetic acid alone gives naphthaldehyde. The epoxide 2 reacts also with MgBr2·OEt2, MeLi/CuI, HX (XBr or Cl) and LiAlH4 with nucleophilic attack at the bis(trimethylsilyl)-substituted carbon.

Vinylbis(silane) 1 reacts with MCPBA in CH2Cl2 at r.t. to afford (3-(naphthalen-2-yl)-2,2-bis(trimethylsilyl)oxiran (2). The compound 2 was reacted with various reagents such as ArSH/MgBr2·OEt2, CH3CN/BF3·OEt2, AcOH/Ac2O/BF3·OEt2, HX (XCl, Br), MgBr2·OEt2, LiAlH4 and MeLi/CuI and give the related products.Figure optionsDownload as PowerPoint slideHighlights
► Epoxidation of 1 with MCPBA in CH2Cl2 resulted bis(trimethylsilyl)epoxide 2.
► Treatment of 2 with thiols in the presence of MgBr2·OEt2 led to preparation of 3 and 4.
► Nucleophilic attack occurs regioselectively at the position α- to silicon.