Allylsilanes in the synthesis of three to seven membered rings: the silylcuprate strategy

• Asunción Barbero,
• Francisco J. Pulido and
• M. Carmen Sañudo

Beilstein J. Org. Chem. 2007, 3, No. 16, doi:10.1186/1860-5397-3-16

• . Five and Six Membered Carbocycles Phenyldimethylsilylcyanocuprate 1, prepared by mixing one equivalent of phenyldimethylsilyllithium and one equivalent of copper(I) cyanide, reacts with 1,2-propadiene (bubbled from lecture bottles) at -40°C leading to the intermediate copper species 2, which on

• different from that observed for phenyldimethylsilylepoxyallylsilanes of type 23, giving nucleophilic substitution at the most substituted carbon of the epoxide (Scheme 6). [18][19] Three and Four Membered Carbocycles Oxoallylsilanes 4–7, 33 and 34, readily available via silylcuprate addition of 2 to enones

• key step is the syn addition of the tin cuprate to the acetylene, which controls the cis stereochemistry required for cyclization. [23] Seven Membered Carbocycles The use of nitriles and imines as electrophiles in the silylcupration of allene provides new alternatives for carbocyclization. Recently