Exploring O-stannyl ketyl and acyl radical cyclizations for the synthesis of γ-lactone-fused benzopyrans and benzofurans
作者:Helen Santoso、Myriam I. Casana、Christopher D. Donner
DOI:10.1039/c3ob42090f
日期:——
The synthesis of a series of γ-lactone-fused benzopyrans and benzofurans, analogues of the pyranonaphthoquinone antibiotics, is reported. Preparation of the heterocycles was achieved by either O-stannyl ketyl or acyl radicalcyclization of benzaldehyde precursors followed by oxidation to give the pyrano- and furanobenzoquinone systems. The observed diastereoselectivity during O-stannyl ketyl radical
Synthesis of novel pyranoquinones using an acyl radical cyclization strategy
作者:Christopher D. Donner、Myriam I. Casana
DOI:10.1016/j.tetlet.2011.12.084
日期:2012.2
Hindered β-benzyloxyacrylates cyclize efficiently providing a tin-free radical cyclization approach to the serine/threonine kinase AKT inhibitor frenolicin B, whilst γ-aryloxy crotonates give good yields of benzopyran-4-ones. This method is applied to the synthesis of a novel tetracyclic analogue of the pyranonaphthoquinone antibiotics.
Cyanative alkene–aldehyde coupling: Ni(0)–NHC–Et2AlCN mediated chromanol synthesis with high cis-selectivity at room temperature
作者:Chun-Yu Ho
DOI:10.1039/b918626c
日期:——
Described are several classes of Ni(0) mediated cyanative alkeneâaldehyde coupling reactions, providing 6-membered cores, which complement existing cyclization technology in several respects. Et2AlCN was used as both a cyclization accelerator and CN source. The NHC ligand may have a positive effect in differentiating reductive elimination and syn-β-hydride elimination.
Tributyltin hydride-mediated radical cyclisation of carbonyls to form functionalised oxygen and nitrogen heterocycles
作者:Jon Bentley、Paul A. Nilsson、Andrew F. Parsons
DOI:10.1039/b202077g
日期:2002.6.7
The tributyltin hydride-mediated cyclisation of unsaturated ethers and aminesbearing an aldehyde or α,β-unsaturated ketone group is reported. Cyclisation proceeds via reversible addition of the tributyltin radical to the carbonyl double bond to form an intermediate O-stannyl ketyl. This nucleophilic radical can add intramolecularly to electron-rich double bonds to form substituted 5- or 6-membered
A one-step strategy for the synthesis of alpha-methenyl ketones from beta-keto sufones is reported. Success of the methodology is elaborated for the synthesis of chromanones and isoflavanones in one-step.