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The Pd(PPh2)4-catalyzed coupling reaction of alkenyl-disiamylboranes with furfuryl chloride in the presence of f-BuOK afforded (E)-furfurylalkenes stereospecifically in good yields.

Pd-catalyzed cross-coupling reactions of chloropyrimidines with alkenylboronic acids readily proceed to give the corresponding alkenylpyrimidines in high to excellent yields. The coupling reaction of 2,4-dichloropyrimidine or 2,4,6-trichloropyrimidine with one equivalent of alkenylboronic acid occurred more easily on 4-position than on 2-position, which implied that the reaction is highly regioselective. The reaction is stereospecific since the configuration of C=C remained intact. The preliminary study on the cross-coupling reactions of 2,4,6-trichlorotriazine with one equivalent of arylboronic acids showed that the reactions afforded the monosubstituted triazines in moderate yields. The effect of steric hindrance of the substitutents on the reactions was found.

The thermal decomposition behavior and kinetic parameters of the exothermic decomposition reactions of the title compound in a temperature-programmed mode have been investigated by means of DSC, TG-DTG and lower rate Thermolysis/FTIR. The possible reaction mechanism was proposed. The critical temperature of thermal explosion was calculated. The influence of the title compound on the combustion characteristic of composite modified double base propellant containing RDX has been explored with the strand burner. The results show that the kinetic model function in differential form, apparent activation energy Ea and pre-exponential factor A of the major exothermic decomposition reaction are 1-a,207.98 kJ*mol−1 and 1015.64 s−1, respectively. The critical temperature of thermal explosion of the compound is 312.87 C. The kinetic equation of the major exothermic decomposition process of the title compound at 0.1 MPa could be expressed as: dα/dT=1016.42 (1–α)e-2.502×104/T As an auxiliary catalyst, the title compound can help the main catalyst lead salt of 4-hydroxy-3,5dinitropyridine oxide to enhance the burning rate and reduce the pressure exponent of RDX-CMDB propellant.

The cross-coupling reaction of trans-alkenylboronic acids with alpha-bromoacetic esters was firstly studied. It was found that using Pd(OAc)(2) as catalyst, a bulky electron-rich phospine, (2-dicyclohexylphospino-biphenyl) as ligand, the reaction can be readily accomplished to give specific (E)-beta,gamma-unsaturated esters in high yields.

An efficient stereoselective aza-Henry reaction of N-tosyl imine, catalyzed by the coordination of diethylzinc with a chiral semi-aza-crown ligand, with moderate to high ee (up to 83%) is reported.

The Suzuki-type cross-coupling reaction of arylboronic acids 3 with ethyl (Z)-3-iodo-4,4,4-trifluoro-2-butenoate 2, which was generated by hydroiodination of available ethyl 4,4,4-trifluoro-2-butynoate 1, to afford ethyl (E)-3-aryl-4,4,4-trifluoro-2-butenoates 4, was studied for the first time. It was found that under the optimum conditions the cross-coupling reaction could readily give 4 as the sole E-isomer in 76–91% yields. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:287–290, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10032

The reactions of 2-chloromethylthiophene (an analog of a benzyl halide) with lithium trialkylalkynylborates gave, after protonation, E-alkenes with a (2-thenyl) substituent in good yields, and the reaction stereo-selectivity was different from that of the reaction of benzyl bromide with an alkynylborate.

Optically active cyclopropanes (e.g. 1) can be prepared by the use of tartaric acid derivatives as chiral auxiliaries in the palladium-catalyzed cross-coupling of optically active cyclopropylboronic acids with electrophiles. The absolute configuration of the chiral carbon atom is retained, and the reaction proceeds with good yields and enantiomeric excesses. R=H, p-Ph, o-CO2 CH3 , p-CO2 CH3 , p-NO2 , o-OCH3 , m-OCH3 .

Copper(I) oxide can effectively co-catalyze the Suzuki type cross-coupling reactions of arylboronic acids with ethyl bromoacetate. As an alternative protocol for introducing the methylenecarboxy group into functionalized molecules, this reaction occurs in the absence of highly toxic thallium compounds or special ligands and should be convenient and practical.

The stereocontrolled dehydrobromination of 1,2-dibromoethyl carboxylates giving (Z)-2-bromovinyl carboxylates could readily be approached by using DBU and a catalytic amount of hydroquinone as a base at −78 °C. The first investigation on the Suzuki-type cross-coupling of (Z)-2-bromovinyl carboxylates as electrophiles with stereodefined alkenylboronic acids provides a novel method for the construction of (Z,E)- or (Z,Z)-conjugated alkadienyl carboxylate moieties, which are often present in a range of natural products.

A simple and efficient synthesis of N-sulfonyl ketimines through a Pd-catalyzed cross-coupling reaction between organoboronic acids and tosylbenzimidoyl chlorides under mild conditions has been developed.

Optically active cyclopropanes (e.g. 1) can be prepared by the use of tartaric acid derivatives as chiral auxiliaries in the palladium-catalyzed cross-coupling of optically active cyclopropylboronic acids with electrophiles. The absolute configuration of the chiral carbon atom is retained, and the reaction proceeds with good yields and enantiomeric excesses. R=H, p-Ph, o-CO2 CH3 , p-CO2 CH3 , p-NO2 , o-OCH3 , m-OCH3 .

4-Substituted 1,2-oxaborol-2(5H)-ols were prepared through copper-catalyzed carbomagnesation of propargyl alcohol, followed by the transmetallation of magnesium to boron in a one-pot procedure. The Suzuki-Miyaura cross-coupling of these new 2,2-disubstituted alkenylboronic acids with aryl halides afforded stereodefined 2,3-disubstituted allyl alcohols in good to excellent yields.

The effect of coordination on the reaction of N-tosyl imines and diethylzinc was studied in detail. It showed that there was strong coordination between N-tosyl imine and diethylzinc. Due to this coordination, N-tosyl imines could be reduced directly through the β-H transferring mechanism by diethylzinc in nonpolar solvents to afford the corresponding secondary amines in excellent yields at mild conditions. The coordination of diethylzinc and N-tosyl imine was hindered by reacting in polar solvents or adding TMEDA to the reaction, it afforded ethylating product partially or exclusively.

The Suzuki–Miyaura type cross‐coupling reactions of various chloropyrimidines with stereodefined alkenylboronic acids giving the corresponding alkenyl‐substituted pyrimidines were studied. The experiments discovered that the reaction is stereospecific and highly regioselective. In the coupling of 2,4‐dichloropyrimidine and 2,4,6‐trichloropyrimidine, the reaction occured at 4‐position prior to 2‐position.

[reaction: see text] Stereospecific cyclopropanation of alkenylboronic esters of pinacol followed by in situ treatment with excess KHF(2) afforded the corresponding potassium cyclopropyl trifluoroborates in high yields, which then underwent Suzuki-Miyaura cross-coupling reactions with aryl bromides to give cyclopropyl-substituted arenes in good yields with retention of configuration. This promises to be a useful method for the synthesis of enantiomerically pure cyclopropanes.

The reactions of 2-chloromethylthiophene (an analog of a benzyl halide) with lithium trialkylalkynylborates gave, after protonation, E-alkenes with a (2-thenyl) substituent in good yields, and the reaction stereo-selectivity was different from that of the reaction of benzyl bromide with an alkynylborate.

A novel method for the synthesis of stereodefined cyclopropyl-substituted alkenes, based on the Suzuki-type cross-coupling reaction between cyclopropylboronic acids and various alkenyl triflates, is described. It was found that the environment of the alkenyl triflate plays an important role in the reaction, and that the use of an appropriate base can make the reaction proceed readily to give stereodefined cyclopropyl-substituted alkenes in good to high yield.

In the presence of Pd(PPh3)4, NaBr and KF·2H2O the cross-coupling reaction of heteroaryl triflates with trans-cyclopropylboronic acids proceeds readily to give pure trans-cyclopropyl heteroarenes in moderate to good yields. The X-ray crystallography of compound 3g and 1H-NMR spectra of all products show that the configuration of the cyclopropyl group was retained during the reaction. Under the same reaction conditions, highly optically active cyclopropyl-substituted heteroarenes (up to 94% ee) were obtained by cross-coupling of heteroary/triflates with enantiomerically enriched cyclopropylboronic acids.

The palladium-catalyzed cross-coupling reaction of cyclopropylboronic acids with acyl chlorides was achieved by the combination of Ag2O and K2CO3 as the base. Highly enantiomerically enriched cyclopropyl ketones (ee >90%) were also obtained by the reaction of corresponding chiral cyclopropylboronic acids.