A Simple Method for the Synthesis of Substituted Benzylic Ketones: Homologation of Aldehydes via the in Situ Generation of Aryldiazomethanes from Aromatic Aldehydes
作者:Steven R. Angle、Martin L. Neitzel
DOI:10.1021/jo000446y
日期:2000.10.1
A general method for the homologation of aldehydes to benzylic ketones has been developed. Aryldiazomethanes were generated in situ in the presence of an aldehyde by simply heating the tosylhydrazones of aromatic aldehydes in the presence of a stoichiometric amount of base in polar protic solvents. The resulting polar protic solvent promoted homologation afforded benzylic ketones in moderate to excellent
Transformation of the B Ring to the C Ring of Bryostatins by Csp<sup>3</sup>–H Amination and <i>Z</i> to <i>E</i> Isomerization
作者:Ji Lu、Yuebao Zhang、WenYu Yang、Qianyou Guo、Lu Gao、Zhenlei Song
DOI:10.1021/acs.orglett.7b02510
日期:2017.10.6
An interesting approach to transform the B ring of bryostatins to the C ring has been developed. The key tactics of the approach feature an intramolecular Csp3–H bond amination to form spirocyclic hemiaminal, which undergoes ring opening to afford the C ring found in bryostatin 17. The subsequent epoxidation/oxidation sequence results in Z to E isomerization of the exo-cyclic enoate, delivering the common
Stereoselective Synthesis of Tetrahydropyrans via Formal [4 + 2]-Cycloaddition: A Comparison of Allylsilane and Crotylsilane
作者:Steven R. Angle、Dominique S. Belanger、Nahla A. El-Said
DOI:10.1021/jo0203342
日期:2002.11.1
two diastereomers with allylsilane, but only a single diastereomer was observed in the case of crotylsilanes. The reaction time for crotylsilanes was longer than that for allylsilanes likely due to the increased steric hindrance. Allylsilanes afforded tetrahydropyrans in 34-67% yields, and crotylsilanes provided products in 0-62% yields.