22256-43-5

The new macrocyclic ligand L (28,29-dimethoxy-27-oxa-8,11,14,17,25,26-hexaazatetracyclo[22.2.1.1(2,6).1(19,23)]nonacosa-2,4,6(28),19,21,23(29),24,26(1)-octaene) has been synthesised. It contains a tetramine chain and the 2,5-bis(2-methoxy-3-metyl-phenyl)-

Palladium/norbornene (Pd/NBE) cooperative catalysis has emerged as a useful tool for preparing poly substituted arenes; however, its substrate scope has been largely restricted to aryl iodides. While aryl bromides are considered as standard substrates for Pd-catalyzed cross coupling reactions, their use in Pd/NBE catalysis remains elusive. Here we describe the development of general approaches for aryl bromide-mediated Pd/NBE cooperative catalysis. Through careful tuning the phosphine ligands and quenching nucleophiles, ortho amination, acylation and alkylation of aryl bromides have been realized in good efficiency. Importantly, various heteroarene substrates also work well and a wide range of functional groups are tolerated. In addition, the utility of these methods has been demonstrated in sequential cross coupling/ortho functionalization reactions, consecutive Pd/NBE-catalyzed difunctionalization to construct penta-substituted aromatics and two-step meta functionalization reactions. Moreover, the origin of the ligand effect in ortho amination reactions has been explored through DFT studies. It is expected that this effort would significantly expand the reaction scope and enhance the synthetic potential for Pd/NBE catalysis in preparing complex aromatic compounds.

An efficient synthetic strategy to access hydroxyl-isochromanone and -isobenzofurans from readily available joint alkene precursors by a regiodivergent one-pot iodocyclization-substitution tandem process is reported. The cyclizations proceed with excellen

Full details on the design, development, and application of a highly stereoselective strategy for the synthesis of isochromanones are reported. The method is based on an asymmetric ortho lithiation with aldehyde electrophiles and utilizes the chiral memor

Disclosed is a new, catalytic, and general methodology for the chemical synthesis of biaryl, heterobiaryl, and polyaryl molecules by the cross-coupling of o-methoxybenzamides with aryl boroneopentylates. The reaction is based on the activation of the unreactive C-OMe bond by the proximate amide directing group using catalytic RuH2(CO)(PPh3)3 conditions. A one-step, base-free coupling process is thereby established that has the potential to supersede the useful two-step directed ortho metalation/cross- coupling reaction involving cryogenic temperature and strong base conditions. High regioselectivity, orthogonality with the Suzuki-Miyaura reaction, operational simplicity, minimum waste, and convenient scale-up make these reactions suitable for industrial applications.

Regioselective alkylation and oxidative rearrangement of isobenzofurans has been achieved to generate substituted 4,8- ihydroxyisochromanones in good yields and with complete regiocontrol.

A series of 4-(3,4-dihydroxyphenyl)-1,2,3,4-tetrahydroisoquinoline derivatives showed potent DA1 agonistic activities. We investigated the structure-activity relationship of the racemic compounds of this series. 4- (3,4-Dihydroxyphenyl)-7-metha

The total synthesis of structural analogues of the unnatural, C-6-hydroxylated isokalafungins and isonanaomycins is described.The new compounds show improved antibiotic activity and support theories for a mechanism of action which base on the formation of

Irradiation of 2-methoxydiphenyldiazomethane 1a in diethyl ether at 10 deg C gave 3-phenyldihydrobenzofuran 3a along with a small amount of the ether adduct 4a, which became the major product when the irradiation was carried out in the ether matrix at -196 deg C.The reaction patterns were dramatically changed as an alkyl group was introduced into the 3-position of substrates 1.Thus, irradiation of 2-methoxy-3-alkyldiphenyldiazomethanes 1b-d in diethyl ether either at 10 deg C or at -196 deg C afforded the corresponding benzofurans 3b-d at the complete expense of the ether adducts 4b-d.The results are nicely explained in terms of the buttressing effect of the 3-alkyl group, which prevents the 2-methoxy group from lying in the plane of the phenyl ring in the precursor molecules and assists the methoxy group in rotating around the C-O bond toward the carbene centre after elimination of N2.Generation of carbenes 2 in methanol at 10 deg C produced O-H insertion adducts 5 as the major product at the expense of benzofurans 3.The ether 5a was formed as a major product in the reaction of carbene 2a with the alcohol matrix at -196 deg C, but the benzofurans 3 became the major product in the irradiation of substrates 1b-d in methanol matrix at -196 deg C.The results are again explicable in terms of the buttressing effect of 3-alkyl substituents on the relative populations of thew rotational isomers of the carbenes 2.The effect of the 3-alkyl group on the reaction of 2,2',5'-trimethoxydiphenylcarbenes 7 which form two kinds of intramolecular C-H insertion products 8 and 9 were studied and the results are again discussed in terms of the buttressing effect.

A general procedure is described for the synthesis of chiral biphenyls via nucleophilic aromatic substitution of an o-methoxy group by an aryl Grignard reagent with an oxazoline as a chiral auxiliary.