Construction of a C(30−38) Dioxabicyclo[3.2.1]octane Subtarget for (+)-Sorangicin A, Exploiting a Regio- and Stereocontrolled Acid-Catalyzed Epoxide Ring Opening
摘要:
In this paper, we report assembly of the novel dioxabicyclo[3.2.1]octane subtarget (-)-2, comprising the signature structural element of the potent antibiotic (+)-sorangicin A (1). The synthesis was achieved in 15 steps (1.5% overall yield) via a series of acid-catalyzed epoxide ring openings, The first, facilitated by the complex of alkyne (+)-3 with Co-2(CO)(8), proceeded in a highly regio- and stereoselective fashion.
A new and more powerfully activating diamine for practical and scalable enantioselective aldehyde crotylsilylation reactions
作者:Linda M. Suen、Michael L. Steigerwald、James L. Leighton
DOI:10.1039/c3sc50714a
日期:——
A new diaminophenol ligand for crotylsilylation reactions with cis- and trans-crotyltrichlorosilane has been developed. The conformational constraints that result from the tethering of the phenol to one of the amino groups attenuate the stereoelectronic effects that reduce activity in the corresponding untethered diaminosilanes, and the resulting crotylsilane reagents are as active as our previously