Disclosed is a cross-coupling reaction method which forms a chemical bond selected from C—N, C—B, C—C, C—O and C—S bonds, the method comprising: preparing an aromatic compound (1) having a leaving group; preparing a compound (2) capable of undergoing a cross-coupling reaction selected from an aromatic amino compound (2-1), a diboronic acid ester or the like (2-2), an aromatic boronic acid or the like (2-3), an aromatic compound (2-4) having a hydroxyl group and an aromatic compound (2-5) having a thiol group; and performing a cross-coupling reaction of the compound (1) with the compound (2) in the presence of a palladium catalyst, a base and a compound (4) having a carbon-carbon double bond or a carbon-carbon triple bond, in the absence of a solvent.

A hydrosilylation iron catalyst prepared from a two-electron ligand (L) and a mononuclear, binuclear, or trinuclear complex of iron indicated by formula (1), Fe having bonds with carbon atoms included in X and the total number of Fe-carbon bonds being 2-10. As a result of using iron, the hydrosilylation iron catalyst is advantageous from a cost perspective as well as being easily synthesized. Hydrosilylation reactions can be promoted under mild conditions by using this catalyst.

Fe(X).sub.a  (1)

(in the formula, each X independently indicates a C2-30 ligand that may include an unsaturated group excluding carbonyl groups (CO groups) and cyclopentadienyl groups, however at least one X includes an unsaturated group, a indicates an integer of 2-4 per Fe atom.)

A hydrosilylation iron catalyst prepared from a two-electron ligand (L) and a mononuclear, binuclear, or trinuclear complex of iron indicated by formula (1), Fe having bonds with carbon atoms included in X and the total number of Fe-carbon bonds being 2-10. As a result of using iron, the hydrosilylation iron catalyst is advantageous from a cost perspective as well as being easily synthesized. Hydrosilylation reactions can be promoted under mild conditions by using this catalyst.

Fe(X).sub.a  (1)

(in the formula, each X independently indicates a C2-30 ligand that may include an unsaturated group excluding carbonyl groups (CO groups) and cyclopentadienyl groups, however at least one X includes an unsaturated group, a indicates an integer of 2-4 per Fe atom.)

Disclosed is a cross-coupling reaction method which forms a chemical bond selected from C—N, C—B, C—C, C—O and C—S bonds, the method comprising: preparing an aromatic compound (1) having a leaving group; preparing a compound (2) capable of undergoing a cross-coupling reaction selected from an aromatic amino compound (2-1), a diboronic acid ester or the like (2-2), an aromatic boronic acid or the like (2-3), an aromatic compound (2-4) having a hydroxyl group and an aromatic compound (2-5) having a thiol group; and performing a cross-coupling reaction of the compound (1) with the compound (2) in the presence of a palladium catalyst, a base and a compound (4) having a carbon-carbon double bond or a carbon-carbon triple bond, in the absence of a solvent.

The present invention relates to a process for the preparation of crisaborole of formula (I): ##STR00001##
by preparing intermediates of formulas (II) and (III): ##STR00002##

Provided is a catalyst which comprises a compound represented by formula (1) and which exhibits activity for at least one type of reaction selected from among hydrosilylation reaction or hydrogenation reaction with respect to an aliphatic unsaturated bond and hydrosilane reduction reaction with respect to a carbon-oxygen unsaturated bond or a carbon-nitrogen unsaturated bond. Formula (1): M.sub.n(L.sub.m) {M represents Fe, Co, or Ni having an oxidation number of 0, L represents an isocyanide ligand represented by formula (2), n denotes an integer of 1-8, and m denotes an integer of 2-12. Formula (2): (CN).sub.x—R.sup.1 (R.sup.1 represents a mono- to trivalent-organic group having 1-30 carbon atoms, optionally being substituted by a halogen atom, and optionally having interposed therein one or more atoms selected from among O, N, S, and Si; and x denotes an integer of 1-3)}.

The invention is directed to methods of converting a carboxylic acid group in a compound, via a redox active ester, to a corresponding boronic ester by treatment with bis(pinacolato)diboron-alkyllithium complex in the presence of a ligand, a Ni(II) salt or a copper salt, and an Mg(II) salt, in the presence of an alkyllithium or a lithium hydroxide or alkoxide salt. The product pinacolato boronate ester can be cleaved to provide a boronic acid. The invention is also directed to methods of preparing various compounds of medical value comprising boronic acid groups, and to novel boronic-acid containing compounds of medicinal value, including an atorvastatin boronic acid analog, a vancomycin aglycone boronic acid analog, and boronic acid containing elastase inhibitors mCBK319, mCBK320, mCBK323, and RPX-7009.

The invention is directed to methods of converting a carboxylic acid group in a compound, via a redox active ester, to a corresponding boronic ester by treatment with bis(pinacolato)diboron-alkyllithium complex in the presence of a ligand, a Ni(II) salt or a copper salt, and an Mg(II) salt, in the presence of an alkyllithium or a lithium hydroxide or alkoxide salt. The product pinacolato boronate ester can be cleaved to provide a boronic acid. The invention is also directed to methods of preparing various compounds of medical value comprising boronic acid groups, and to novel boronic-acid containing compounds of medicinal value, including an atorvastatin boronic acid analog, a vancomycin aglycone boronic acid analog, and boronic acid containing elastase inhibitors mCBK319, mCBK320, mCBK323, and RPX-7009.

The present invention provides PC.sub.NHCP pincer metal complexes, which are useful as catalysts in various chemical reactions such as hydrogen isotope exchange (HIE) in C(sp.sup.3)-H and/or C(sp.sup.2)-H bond of an organic compound, e.g., a pharmaceutically active compound; hydroboration of alkynes with excellent selectivity; and alkene isomerization with high stereo- and regioselectivity.

A new set of bench-stable fluoroalkylphosphines that directly convert C—H bonds in pyridine building blocks, drug-like fragments, and pharmaceuticals, into fluoroalkyl derivatives. No pre-installed functional groups or directing motifs are required. The reaction tolerates a variety of sterically and electronically distinct pyridines and is exclusively selective for the 4-position in most cases. The reaction proceeds via initial phosphonium salt formation followed by sp.sup.2-sp.sup.3 phosphorus ligand-coupling, an underdeveloped manifold for C—C bond formation.