Two lactone formation reactions from 1,3-dioxin-4-ones having hydroxyalkyl group at the 6-position: Difference in ring opening and closure
摘要:
Two methods (A: ring opening to acylketenes followed by intramolecular ketene trapping and B: methoxide-mediated ring opening followed by cyclization of the hydroxy esters thus formed) have become available for the synthesis of lactones and/or cyclic ethers from 1,3-dioxin-4-ones having 1-approximately 4-hydroxyalkyl group at the 6-position. Mechanism and scope of both methods have been clarified.
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。
Optically active 2,2-dimethyl-1,3-dioxin-4-ones and method for preparing
申请人:Chisso Corporation
公开号:US05256800A1
公开(公告)日:1993-10-26
There are provided novel and optically active 2,2-dimethyl-1,3-dioxin-4-ones which are useful as starting materials for physiologically active compounds, functional materials or the like. Furthermore, a method for preparing an optically active compound comprises reacting a racemic 1,3-dioxin-4-one with vinylacetate in the presence of lipase to resolve the racemic compound into optically active compound represented by the formula (3) ##STR1## and an optically active compound represented by the formula (4) ##STR2## which is an antipode of the compound represented by the formula (3).
Optically active 1,3-dioxin-4-ones have the formula :
wherein n is a value of 1 to 3 ; X is a hydrogen atom, a benzyloxy group, a chlorine atom or N3 ; Y is a hydrogen atom or an acetyl group ; the symbol * represents an asymmetric carbon atom ; and the substituent chain is present at the 5- or 6-position ; provided that when n is 1 and X is a benzyloxy group, a chlorine atom or N3, the substituent is present at the 6-position ; when n is 2 and X is a hydrogen atom the substituent is present at the 5-position ; and when n is 3 and X is a hydrogen atom, the substituent is present at the 6-position.
Various methods for the preparation are disclosed.