488703-70-4Relevant articles and documents
Total synthesis of (+)-brasilenyne. Application of an intramolecular silicon-assisted cross-coupling reaction
Denmark, Scott E.,Yang, Shyh-Ming
, p. 12432 - 12440 (2007/10/03)
The first enantioselective total synthesis of (+)-brasilenyne (1) has been achieved in 19 linear steps, with 5.1% overall yield from L-(S)-malic acid. The construction of the oxonin core containing a 1,3-cis, cis diene unit was accomplished with a tandem ring-closing metathesis/silicon-assisted intramolecular cross-coupling reaction. In addition, a key propargylic stereogenic center was created through a novel, highly diastereoselective ring opening of a 1,3-dioxolanone promoted by TiCl4. This reaction proceeded through an oxocarbenium ion intermediate and the asymmetric induction was fully controlled by L-malic acid residue. The C(8) stereogenic center was set by a reagent-controlled asymmetric allylboration.
