Synthesis of 1,2,4-Trioxepanes and 1,2,4-Trioxocanes via Photooxygenation of Homoallylic Alcohols1
摘要:
Homoallylic alcohols 4a-d, easily accessible in two steps from cyclopropyl methyl ketone, underwent a highly regioselective reaction with singlet oxygen to yield gamma-hydroxyhydroperoxides 5a-d in 57-72% yield. Acid-catalyzed reaction of 5a-d with acetone, cyclopentanone, and cyclohexanone furnished 1,2,4-trioxepanes 8a-d, 9a-d, and 10a-d in good yields. Homoallylic alcohol 12 also underwent a highly regioselective photooxygenation to yield delta-hydroxyhydroperoxide 13 in 67% yield, which on reaction with acetone, cyclopentanone, and cyclohexanone, furnished 1,2,4-trioxocanes 16-18 in 41-55% yield.
Herein we report the palladium-catalyzed isomerization of highly substituted allylic alcohols and alkenyl alcohols by means of a single catalytic system. The operationally simple reaction protocol is applicable to a broad range of substrates and displays a wide functional group tolerance, and the products are usually isolated in high chemical yield. Experimental and computational mechanistic investigations
Intramolecular N–Me and N–H aminoetherification for the synthesis of <i>N</i>-unprotected 3-amino-O-heterocycles
作者:Mahesh P. Paudyal、Mingliang Wang、Juha H. Siitonen、Yimin Hu、Muhammed Yousufuddin、Hong C. Shen、John R. Falck、László Kürti
DOI:10.1039/d0ob02122a
日期:——
A mild Rh-catalyzed method for synthesis of cyclic unprotected N–Me and N–H 2,3-aminoethers using an olefin aziridination–aziridine ring-opening domino reaction has been developed. The method is readily applicable to the stereocontrolled synthesis of a variety of 2,3-disubstituted aminoether O-heterocyclic scaffolds, including tetrahydrofurans, tetrahydropyrans and chromanes.
Nickel-Catalyzed Arylboration of Alkenylarenes: Synthesis of Boron-Substituted Quaternary Carbons and Regiodivergent Reactions
作者:Liang-An Chen、Alan R. Lear、Pin Gao、M. Kevin Brown
DOI:10.1002/anie.201904861
日期:2019.8.5
A method for the construction of boron‐substituted quaternary carbons or diarylquaternary carbons by arylboration of highly substituted alkenylarenes is presented. A wide range of alkenes and arylbromides can participate in this reaction thus allowing for a diverse assortment of products to be prepared. In addition, a solvent dependent regiodivergent arylboration of 1,2‐disubstituted alkenylarenes
Hot water-promoted cyclopropylcarbinyl rearrangement facilitates construction of homoallylic alcohols
作者:Pei-Fang Li、Cheng-Bo Yi、Jin Qu
DOI:10.1039/c5ob00305a
日期:——
H2O–1,4-dioxane and without an additional catalyst, the rearrangements of various types of cyclopropylcarbinols were attempted. It was found that the reactions generally gave homoallylic alcohols in good to very high chemical yields. Rearrangements of bicyclic or tricyclic cyclopropylcarbinols readily gave the desired ring-expanded cyclic homoallylic alcohols which are difficult to synthesize by other
Ir‐phosphinomethyl‐oxazoline complexes have been identified as efficient, highlyenantioselective catalysts for the asymmetric hydrogenation of 3,3‐disubstituted allylicalcohols and related homoallylic alcohols. In contrast to other N,Pligand complexes, which require weakly coordinating solvents, such as dichloromethane, these catalysts perform well in more ecofriendly THF or 2‐MeTHF. Their synthetic