Spiropentadiene, or bowtiediene, is a hydrocarbon with formula . The simplest spiro-connected diene, it is very unstable—decomposing even below −100 °C—due to its high bond strain and does not occur in nature. Its synthesis was reported in 1991.
Spiropentadiene, or bowtiediene, is a hydrocarbon with formula . The simplest spiro-connected diene, it is very unstable—decomposing even below −100 °C—due to its high bond strain and does not occur in nature. Its synthesis was reported in 1991.
==Synthesis== Spiropentadiene was synthesised from bistrimethylsilylpropynone 1 by reaction with p-toluenesulfonylhydrazide to tosylhydrazone 2 followed by treatment with sodium cyanoborohydride to allene 3 and followed by two successive reactions with chlorocarbene generated from methyllithium and dichloromethane to spiro compound 5. Spiropentadiene was trapped in a liquid nitrogen trap after reaction with TBAF in a double elimination reaction. 645px|Spiropentadiene synthesis
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).