ABSTRACT
Making use of temperature-controlled thiation as a key operation, a simple route to 2-aminothiophenes or thieno[2,3- c]isothiazoles has been newly developed wherein the 2-aminothiophene nucleus was formed through an initial formation of thioamide followed by a 5-exo-dig addition to the tethered alkyne; however, under harsher thermal conditions, excess sulfur-transferring reagents enabled further oxidative thiation to generate the corresponding thieno[2,3- c]isothiazoles.
ABSTRACT
A new N-hydroxyphthalimide (NHPI)/Co(II)-catalyzed protocol, mechanistically involving a sequence of α-hydrogen abstraction, 5-exo-dig cyclization, oxygen capture, hydrogen transfer, and 1,4-dehydration, has been developed to facilitate aerobic oxidation of aryl-, silyl-, and alkyl-capped alkynyl α-cyano alkanone systems to the corresponding highly functionalized products in an effective manner, thus turning this novel chain reaction, originally occurring spontaneously in low yields, into a practical methodology.
ABSTRACT
Making use of a tandem free radical cyclization process mediated by Mn(OAc)3 as a key operation, the total synthesis of retrojusticidin B, justicidin E, and helioxanthin has been concisely achieved in four or five steps in an overall yield of 45, 33 and 44%, respectively, from a common starting material 5.
Subject(s)
Dioxolanes/chemical synthesis , Lignans/chemical synthesis , Naphthalenes/chemical synthesis , Catalysis , Cyclization , Dioxolanes/chemistry , Lignans/chemistry , Molecular Structure , Naphthalenes/chemistryABSTRACT
The radical cascade protocol of the α-cyano α-TMS/aryl-capped alkynyl aryl ketones promoted by tert-butyl hydroperoxide under catalysis with tetrabutylammonium iodide in refluxing benzene has been developed, leading to the construction of a variety of highly functionalized [6,6,5] tricyclic frameworks in an efficient manner.
Subject(s)
Alkynes/chemistry , Hydrocarbons, Iodinated/chemistry , Ketones/chemistry , Quaternary Ammonium Compounds/chemistry , tert-Butylhydroperoxide/chemistry , Catalysis , Combinatorial Chemistry Techniques , Cyclization , Molecular Structure , StereoisomerismSubject(s)
Hematopoietic Stem Cell Mobilization , Receptors, CXCR4/antagonists & inhibitors , Animals , Benzylamines , Cyclams , Drug Evaluation, Preclinical , Hematopoietic Stem Cells/cytology , Heterocyclic Compounds/chemistry , Heterocyclic Compounds/pharmacology , Injections, Subcutaneous , Male , Mice , Mice, Inbred C57BL , Polyamines/chemistry , Pyrimidines/chemistry , Quinazolines/chemical synthesis , Quinazolines/chemistry , Quinazolines/pharmacology , Receptors, CXCR4/metabolism , Regenerative MedicineABSTRACT
Novel preparation of tetrasubstituted furans, starting from the Michael acceptors, tributylphosphine, and acyl chlorides, is realized. A broad range of highly functional furans can be efficiently generated in one step at room temperature within 10 min to 21 h in moderate to high yields (60-99%). The reaction was proposed to proceed via intramolecular Wittig-type reactions, using phosphorus ylides as intermediates.
