O-Silylated Enolates - Versatile Intermediates for Organic Synthesis
作者:Jerald K. RASMUSSEN
DOI:10.1055/s-1977-24284
日期:——
Recent developments in the preparation and reactions of silyl enol ethers derived from aldehydes, ketones, and carboxylic acids and esters are discussed. These versatile compounds provide tremendous potential as synthetic enol equivalents. 1. Synthesis of Silyl Enol Ethers 1.1. Preparation from Enolates 1.2. Preparation from Hydrosilanes 1.3. Preparation from Other Silylating Agents 1.4. Preparation by Thermal Rearrangements 2. Synthesis of Ketene Silyl Acetals 2.1. Preparation from α-Anions and Dianions 2.2. Preparation by Hydrosilylation 3. Reactions of Silylated Enols 3.1. Preparation of Directed Enolates 3.2. Addition of Halides to the Double Bond 3.3. Reactions with Hydrogen Halides 3.4. Cycloaddition Reactions 3.5. Oxidation of Silyl Enol Ethers 3.6. Titanium(IV) Chloride Promoted Reactions 3.7. Thermal Rearrangements of Ketene Silyl Acetals 4. Conclusion
A General Synthesis of<i>S</i>-(β-Oxoalkyl)<i>O,O</i>-Dialkyl Thio- and Dithiophosphates
作者:P. Dybowski、A. Skowrońska
DOI:10.1055/s-1990-26957
日期:——
A novel, general synthesis of S-(β-oxoalkyl) and S-(β-oxocycloalkyl) O,O-dialkyl thio- and dithiophosphates based on the reaction of silyl enol ethers with O,O-dialkyl chlorothio- and O,O-dialkyl bromodithiophosphonates is described.
A general synthesis of a new class of compounds Se-(β-oxoalkyl) O,O-dialkyl selenophosphates based on selenophosphorylation of silyl enol ethers with the chloroselenotrialkoxyphosphonium chlorosulfide 3 is described.
Three-Component Coupling Approach to Trachyspic Acid
作者:Daniel C. Schmitt、Leighann Lam、Jeffrey S. Johnson
DOI:10.1021/ol202002r
日期:2011.10.7
Three-component coupling of the lithium enolate of t-BuOAc, silyl glyoxylate, and an alpha,beta-unsaturated ketone enables the rapid construction of the trachyspic acid carbon skeleton. A 3,4-disubstituted isoxazole is utilized to mask the C7/C9 dicarbonyl. New enolsilane/nitrile-oxide cycloadditions enable the preparation of various 3,4-disubstituted isoxazoles that are challenging to access by other means.
Synthetic methods. VIII. Hydroxylation of carbonyl compounds via silyl enol ethers
作者:Alfred Hassner、Robert H. Reuss、Harold W. Pinnick