Synthesis of β-Hydroxynaphthoate Derivatives from Ketodioxinones via Benzyne Acyl-Alkylation and Aldol Condensation Cascade
作者:Hiroshi Takikawa、Arata Nishii、Keisuke Suzuki
DOI:10.1055/s-0035-1562514
日期:2016.10
functionalized β-hydroxynaphthoate derivatives are prepared by a two-step protocol: (1) acyl-alkylation of benzynes with ketodioxinones and (2) intramolecular aldol condensation. The substitution pattern of the products is related to polycyclic natural products derived from the type-II polyketide biosynthesis. A variety of highly functionalized β-hydroxynaphthoate derivatives are prepared by a two-step protocol:
致力于纪念Jean F. Normant教授 抽象的 通过两步操作方案可以制备多种高度官能化的β-羟基萘甲酸酯衍生物:(1)苯并炔酮与酮二恶英酮的酰基烷基化作用和(2)分子内醛醇缩合反应。产品的取代方式与源自II型聚酮化合物生物合成的多环天然产品有关。 通过两步操作方案可以制备多种高度官能化的β-羟基萘甲酸酯衍生物:(1)苯并炔酮与酮二恶英酮的酰基烷基化作用和(2)分子内醛醇缩合反应。产品的取代方式与源自II型聚酮化合物生物合成的多环天然产品有关。
Total synthesis and structure revision of deacetylravidomycin M
Total synthesis of the unnatural enantiomer of deacetylravidomycin M was accomplished. The key steps include, (1) aryl C-glycosidation of the azido-bearing fucosyl acetate 2 by using catalytic Sc(OTf)3, (2) the [2+2] cycloaddition reaction of alkoxybenzyne bearing an azido sugar to ketene silyl acetal, and (3) the ring expansion reaction of alkoxybenzocyclobutenone. The synthesis revealed that the
s: Sc(OTf) 3 was found to be an efficientcatalyst for the C-glycosylation of phenols. Reactions of various functionalized phenols and glycosyl acetates, including an azido-bearing one, are achieved by using a catalyticamount of Sc(OTf) 3 (10 mol % for neutral sugars or 50 mol% for an azido sugar) under mild conditions.
Facile Access to Versatile Polyaromatic Building Blocks: Selectively Protected Benzocyclobutenedione Derivatives via Regioselective [2+2] Cycloaddition of -Alkoxybenzyne and Ketene Silyl Acetal
facile, divergent access to highly oxygenated benzocyclobutene derivatives was developed via the regioselective [2+2] cycloaddition of α-alkoxybenzynes and ketene silyl acetals. The cycloadducts could be converted to selectively protected alkoxybenzocyclobutenediones, an attractive class of compounds for the synthesis of polyaromatic compounds. As one possible application, divergent access to a regioisomer
Studies are reported on the use of either a 7-exo radical cyclization or an intramolecular Heck reaction as the key step for the construction of the benzophenone fragment of the PKC inhibitor, balanol. Whereas, the former approach was unsuccessful, the Heck reaction proved to be viable for the coupling of two fully functionalized aryl subunits affording regioselectively a biaryl seven-membered lactone