25 January 2011 (online)
The Danishefsky’s diene, trans-1-methoxy-3-trimethylsiloxy-1,3-butadiene (also known as Kitahara diene), was first introduced by Danishefsky and Kitahara in 1974. [¹] Since the diene is very electron-rich it is used as a very reactive reagent in Diels-Alder reactions. The methoxy group accounts for the regiospecificity observed in the Diels-Alder reaction, since the electrophilic carbon to which it is attached will react preferentially with the most nucleophilic atom of the dienophile. The electron-donating nature of this diene confers high reactivity and orientational specificity in its reaction with unsymmetrical dienophiles.
The high reactivity coupled with the easy availability makes 1-methoxy-3-trimethylsiloxy-1,3-butadiene a potentially very important reagent in organic synthesis. Its first synthesis was reported by Danishefsky and Kithara starting from 4-methoxy-3-buten-2-one in the presence of trimethylsilyl chloride and zinc chloride (Scheme [¹] ). [²]
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