作者:Steven D. Burke、David M. Armistead、Frank J. Schoenen、John M. Fevig
DOI:10.1016/s0040-4020(01)90568-x
日期:1986.1
A new method for the stereoselective synthesis of dihydropyrans of various substitution patterns is described, involving the Ireland ester enolate Claisen rearrangements of 6-alkenyl-1,4-dioxan-2-ones. The method has been applied to an enantioselective synthesis of the “left-wing” tetrahydropyran portion 2 of the ionophore antibiotic indanomycin (1). The synthetic sequence employed for the production
A short and convergent strategy for the stereoselective total synthesis of biologically active natural product carolacton has been accomplished. Our synthesis highlights the Urpi acetal aldol, Crimmins aldol, Ireland–Claisen rearrangement, TiCl4-assisted aldol followed by β-hydroxy elimination to construct C7–C8 olefin, and ring-closing metathesis as the key steps for achieving the target molecule
作者:Martin G. Banwell、Rajaratnam Premraj、Malcolm D. McLeod、Gregory W. Simpson
DOI:10.3987/com-12-12597
日期:——
The total synthesis of the methyl ester, 35, of herboxidiene (1, a.k.a. GEX1A and TAN-1609), a polyketide displaying both herbicidal and anti-tumor activity, is described. The convergent reaction sequence involves, in its closing stages, the union of the phosphine oxide 3 with the aldehyde 21 to deliver, via a Horner-Wittig reaction with accompanying epimerization at C12, compound 33 that after deprotection affords an alcohol, 34, capable of participating in a regio- and diastereo-selective epoxidation reaction to give target 35. Phosphine oxide 3 was prepared via the intramolecular hetero-Michael addition of a secondary alcohol to a tethered and Z-configured acrylate while aldehyde 21 was generated, in the crucial step of the relevant reaction sequence, via an Ireland-Claisen rearrangement reaction.