Formal Total Synthesis of the Polyketide Macrolactone Narbonolide
作者:Lakshmanan Venkatraman、Courtney C. Aldrich、David H. Sherman、Robert A. Fecik
DOI:10.1021/jo050924a
日期:2005.9.1
An improved synthesis of (3S)-3-dihydronarbonolide is reported that constitutes a formal total synthesis of the 14-membered macrolactone antibiotic narbonolide. The key step was an intramolecular Nozaki−Hiyama−Kishi coupling to accomplish macrocyclization in improved yield. The high level of convergence will also allow us to rapidly synthesize narbonolide analogues for the study of enzymes in the pikromycin
Reversal of aldehyde diastereofacial selectivity in a methyl ketone aldol reaction. Application to the synthesis of the calyculin spiroketal
作者:David A. Evans、James R. Gage
DOI:10.1016/s0040-4039(00)97005-9
日期:1990.1
It has been observed that aldehyde diastereofacialselectivity in a methyl ketone aldol reaction can be fully regulated under appropriate conditions. Addition of the lithium enolate provided the product derived from apparent chelation control, while Lewis acid-promoted addition of the derived silyl enolether afforded the Felkin-Anh diastereomer. Application of this methodology to the ongoing synthesis
NHC–Cu-Catalyzed Protoboration of Monosubstituted Allenes. Ligand-Controlled Site Selectivity, Application to Synthesis and Mechanism
作者:Fanke Meng、Byunghyuck Jung、Fredrik Haeffner、Amir H. Hoveyda
DOI:10.1021/ol4004178
日期:2013.3.15
Two types of NHC-Cu complexes catalyze protoborations of terminal allenes to afford valuable 1,1- or trisubstituted vinylboron species with high site selectivity and stereoselectivity. The scope of the method, application to natural product synthesis, and mechanistic basis for the observed selectivity trends are presented.
EVANS, DAVID A.;GAGE, JAMES R., TETRAHEDRON LETT., 31,(1990) N3, C. 6129-6132