146566-78-1Relevant articles and documents
Application of the steric directing group strategy to the stereoselective synthesis of the octahydronaphthalene substructure of kijanolide and tetronolide
Roush, William R.,Brown, Bradley B.
, p. 2268 - 2278 (2007/10/02)
A highly stereoselective synthesis of the kijanolide/tetronolide octahydronaphthalene substructure 4 has been completed. The synthesis proceeds in 16 steps from L-glyceraldehyde acetonide (8), with 88% stereoselectivity and in 11% overall yield. Key steps are the following: (1) the asymmetric crotylborations of 8 and 12 that introduce the C(5), C(6), and C(8) stereocenters of 4; (2) the modified Suzuki coupling of vinylboronic acid 36 and dibromo olefin 31 that establishes the conjugated triene unit and introduces the C(9) Br steric directing group in a single operation; and (3) the highly stereoselective intramolecular Diels-Alder cycloaddition of tetraene 7. Stereochemical information obtained from the intramolecular Diels-Alder reactions of 25 and 26 provides a framework for rationalizing the role of the C(5) acetoxy group and the C(9) Br substituent on the stereoselectivity of the intramolecular Diels-Alder reaction of 7.