Total Synthesis of (−)-Spinosyn A: Examination of Structural Features That Govern the Stereoselectivity of the Key Transannular Diels−Alder Reaction
作者:SusAnn M. Winbush、Dustin J. Mergott、William R. Roush
DOI:10.1021/jo7024515
日期:2008.3.1
The TDA cyclizations of 12 (which lacks the C(8)-OTBS unit of 9), 13 (which lacks the C(6)-Br substituent of 12), and 14 (which lacks the C(6)-Br and C(21)-Et substituents of 12) were also studied. Macrocycles 12 and 13 served as precursors to (−)-spinosyn A and the (−)-spinosyn A aglycon (34), respectively. It is striking that substrates 12−14 give very similar distributions of transannular Diels−Alder