Synthesis of allene triazole through iron catalyzed regioselective addition to propargyl alcohols

Allene triazole derivatives were successfully synthesized for the first time through iron catalyzed regioselective triazole addition to tertiary propargyl alcohols. The reaction proceeds under mild conditions, giving the desired allene-triazoles in good to excellent yields (up to 96%). The resulting allene-triazoles were confirmed by X-ray crystallography and indicated improved stability.     

Ruthenium catalyzed transformation of alcohols to esters and lactones

Homogeneous catalytic oxidative condensation of alcohols and diols to their corresponding esters and lactones has been accomplished using RuH₂(PPh₃)₄.     

Lewis acid catalyzed regioselective ring opening of azetidines with alcohols and thiols

An efficient synthesis of amino ethers and amino thioethers has been achieved via the ring cleavage of N-tosylazetidines with alcohols or thiols. The reactions were studied in the presence of various Lewis acids and BF₃·OEt₂ was found to be the most efficient. The products were obtained in modest to good yields under very mild conditions in 5-15 min.     

Ruthenium catalyzed synthesis of secondary or tertiary amines from amines and alcohols

Unsymmetrical secondary and tertiary amines are prepared by the ruthenium catalyzed reaction of alcohols with amines, which provides highly efficient method for synthesis of cyclic amines.     

Highly regioselective ring opening of epoxides with alcohols catalyzed by organotin phosphate condensates

Organotin phosphate condensates proved to catalyze the ring opening reaction of epoxides with alcohols in a highly regioselective manner.     

Indium-mediated reaction of trialkylsilyl propargyl bromide with aldehydes: highly regioselective synthesis of allenic and homopropargylic alcohols

High regioselective preparation of either the allenic alcohols or homopropargylic alcohols using the indium-mediated reaction of trialkylsilyl propargyl bromides with various aldehydes has been accomplished. By just changing the silyl groups and the reaction conditions, both the allenic and homopropargylic alcohols can be obtained in high regioselectivities.     

Electrochemically catalyzed synthesis of cyclic carbonates from CO2 and propargyl alcohols

A convenient and efficient electrochemical method has been developed for the synthesis of the α-alkylidene cyclic carbonates from carbon dioxide (CO₂) and propargyl alcohols at room temperature. The electrosynthesis was successfully carried out with a copper anode and a nickel cathode in an undivided cell containing n-Bu₄NBr-MeCN electrolyte with a constant current under 3 MPa pressure of CO₂, and the α-alkylidene cyclic carbonates were obtained in good to excellent isolated yields in the secondary and tertiary terminal propargylic alcohols cases. The experimental results show that the electrogenerated Cu⁺ ions and strong bases in situ could efficiently catalyze or promote the coupling reaction under the cooperation of electrolytic medium MeCN and supporting electrolyte n-Bu₄NBr. The plausible mechanism of the coupling reaction was also discussed briefly.     

A highly regioselective palladium-catalyzed hydrophosphination of alkynes using a diphosphine-hydrosilane binary system

A novel transition-metal-catalyzed hydrophosphination of terminal alkynes using a diphosphine-hydrosilane binary system takes place regioselectively to provide vinylic phosphines, which undergo air oxidation during workup, affording the corresponding vinylphosphine oxides in good yields. In this hydrophosphination, hydrosilanes act as a useful hydrogen source, and furthermore, small amounts of oxygen is required to accomplish the reaction efficiently.     

Ruthenium catalyzed synthesis of enaminones

The Grubbs first-generation catalyst has been found to be an effective catalyst for the synthesis of enaminones by coupling thioamides with α-diazodicarbonyl compounds. The reaction is successful in converting primary, secondary, and tertiary thioamides into their corresponding enaminones. The reaction is also suitable for the synthesis of chiral enaminones.     

Vanadium-catalyzed addition of propargyl alcohols and imines

A Mannich-type addition of propargylic alcohols and N-methoxycarbonylimines has been achieved by using a vanadium catalyst. The reactivity of the vanadium catalyst could be modulated by modifying the silanol ligands to avoid the background reaction. The strategy described herein provides an atom-economical access to beta-aryl-substituted Z-enones with an allylic amino functional group, which are not readily accessible with other methods.     

Ruthenium(III) chloride catalyzed acylation of alcohols, phenols, thiols, and amines

Ruthenium(III) chloride catalyzes the acylation of a variety of phenols, alcohols, thiols, and amines under mild conditions. Some of the major advantages of this method are high yields, short reaction times, ease of operation, and compatibility with other protecting groups.     

Rhenium-catalyzed coupling of propargyl alcohols and allyl silanes

A mild method for the regioselective coupling of propargyl alcohols and allylsilanes is described. The method employs an air- and moisture-tolerant rhenium-oxo complex ((dppm)ReOCl3) as a catalyst for the formation of sp3-carbon-sp3-carbon bonds without the need for prior activation of the propargyl alcohol as a halide or pseudohalide. The stability of the high oxidation state rhenium complex allows for simple reisolation and reuse of the catalyst. A broad range of functional groups is tolerated including aryl halides, olefins, esters, and acid-labile functional groups such as acetals. Furthermore, displacement of the alcohol occurs preferentially even in the presence of other electrophiles such as primary alkyl halides and conjugated esters. The use of enantiopure crotylsilanes as coupling partners allows for the asymmetric construction of two adjacent stereocenters. The potential of this reaction is demonstrated in an asymmetric synthesis of delta-lactone, di-O-methylcalopin.     

Iron-catalyzed ene-type propargylation of diarylethylenes with propargyl alcohols

The diarylalkenyl propargylic complex framework has been found in many natural products and medicinal regents. Herein, we have disclosed an unprecedented FeCl(3) catalyzed ene-type reaction of propargylic alcohols with 1,1-diaryl alkenes which enabled us to furnish a diarylalkenyl propargylic complex framework in moderate to high chemical yields (up to 98%).     

Synthesis of β-amino alcohols by regioselective ring opening of arylepoxides with anilines catalyzed by cobaltous chloride

CoCl₂ has been used as a mild and effective catalyst for regioselective ring opening of oxiranes with anilines to synthesize β-amino alcohols in good yields.     

Heteropolyacid-catalyzed direct deoxygenation of propargyl and allyl alcohols

The combination of H(3)[PW(12)O(40)]·nH(2)O (1 mol %) and Et(3)SiH led to the direct catalytic deoxygenation of propargyl alcohols, in which proper solvent selection Cl(CH(2))(2)Cl vs CF(3)CH(2)OH was the key to obtaining better product yields. Under similar conditions, the deoxygenation of allyl alcohols proceeded to give thermodynamically stable alkenes with migration of the double bonds in good yields.     

Microwave-enhanced sulphated zirconia and SZ/MCM-41 catalyzed regioselective synthesis of beta-amino alcohols under solvent-free conditions

A solvent-free approach for the regioselective synthesis of beta-amino alcohols in shorter reaction times and higher yields, compared to conventional heating is described. It involves microwave (MW) exposure of undiluted reactants in the presence of sulphated zirconia (SZ) or sulphated zirconia over MCM-41 (SZM) as catalyst. Both acid materials can be easily recovered and reused.     

Regioselective double hydrophosphination of terminal arylacetylenes catalyzed by an iron complex

The first catalytic double hydrophosphination of alkynes was achieved by reaction with diarylphosphines in the presence of an iron catalyst. The double hydrophosphination proceeded regioselectively and effectively for various secondary arylphosphines and terminal alkynes to give 1,2-bisphosphinoethane derivatives.