Tetracyanoethylene, diene synthesis with

The first reference to 2-trimethylsilyloxy-l,3-butadiene (1) was a report2 of its reaction with tetracyanoethylene by Cazeau and Frainnet without mention of any experimental details. Later, Conia3 reported its synthesis in 50% yield with only a reference made to the usual House procedure4 for silyl enol ethers. The diene 1 has also been prepared using lithium diisopropylamide as base and chlorotrimethylsilane in tetrahydrofuran-ether (1 1) in yields up to 65%, but on a smaller scale.s... 

In the 1970s and 1980s, it was discovered that electron-deficient alkenes, such as tetracyanoethylene (TCNE, 55) reacted with metallated alkynes 54 to furnish a metallated hexasubstituted 1,3-diene unit 56, an overall transformation akin to enyne metathesis (Scheme 1.8) [37, 39]. In a recent (2012) addition to this work, the Bruce group reported the synthesis of a ruthenated [3]dendralene 58 via insertion of phenylacetylene (57) into 56 (Scheme 1.8) [38]. The metallated dendralene synthesis is low yielding and, as yet, an isolated example, but presents an interesting avenue for future investigations. 

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