1024019-05-3Relevant academic research and scientific papers
Utilization of a Michael addition: Dipolar cycloaddition cascade for the synthesis of (±)-cylindricine C
Flick, Andrew C.,Arevalo Caballero, Maria Jose,Padwa, Albert
, p. 1871 - 1874 (2008)
A new approach to the marine alkaloid (±)-cylindricine C has been devised. The key element of the synthesis consists of a Michael addition/ dipolar cycloaddition cascade between 2,3-bis(phenylsulfonyl)-1,3-butadiene and 9-triisopropylsilanyloxy-non-1-en-5-one oxime. The resulting cycloadduct was converted into (±)-cylindricine C by a sequence of reactions including a reductive cyclization, intramolecular enolate alkylation, and conjugate addition to introduce the n-hexyl side chain.
A conjugate addition/dipolar-cycloaddition cascade sequence for the synthesis of (±)-cylindricine C
Flick, Andrew C.,Arevalo Caballero, Maria José,Padwa, Albert
experimental part, p. 3643 - 3650 (2010/07/04)
An efficient stereocontrolled route to (±)-cylindricine C is described. Reaction of 9-hydroxynon-1-en-5-one oxime with 2,3-bis(phenylsulfonyl)-1,3-butadiene affords a 7-oxa-1-azanorbornane cycloadduct in high yield. The formation of the bicyclic isoxazolidine arises from conjugate addition of the oxime onto the diene to give a transient nitrone that spontaneously undergoes an intramolecular dipolar cycloaddition. The resulting cycloadduct derived from the cascade sequence was converted into (±)-cylindricine C by: (1) a reductive-cyclization to set the BC-ring skeleton, (2) a base-induced cyclization to construct the tricyclic core, and (3) an oxidation-conjugate addition of the n-hexyl side chain to complete the synthesis.
