Reactions of macrocyclic rhodium carbenoids: regioselective synthesis of indol-3-yl macrocyclic lactones and cryptands

A wide variety of new macrocyclic diazocarbonyl compounds with various spacers was synthesized. Macrocyclic rhodium(II) carbenoid insertion with various substituted indoles was performed to afford regioselectively, indol-3-yl macrocyclic di- or tetralactones (C3-alkylation). Double carbenoid insertion was also performed to afford indolyl cryptand molecules.     

Convenient method for the functionalization of the 4- and 6-positions of the androgen skeleton

The preparation and reactivity of steroidal vinyldiazo compounds is reported, providing a convenient, substituent tolerant, chemo- and stereoselective entry into 4- and 6-substituted androgen analogues from a common precursor. Under dirhodium catalysis, O-H insertion occurs at the carbenoid site, leading to 4-substituted steroids, but under silver catalysis, O-H insertion occurs at the vinylogous position, leading to 6-substituted steroids.     

Double O-H insertion reactions of cyclic rhodium carbenoids: diastereoselective synthesis of macrocyclic oxindoles

Double O-H insertion reactions of cyclic diazo amides 1 and dihydroxy compounds 2 in the presence of rhodium(II) acetate catalyst have been achieved, which ultimately led to the facile synthesis of prototype bis(3-oxy-1,3-dihydro-2H-indol-2-one) systems. This facile double O-H insertion reaction protocol was successfully applied to synthesize several C₂-symmetric macrocycles having oxindole units incorporated with complete diastereoselectivity.     

Hypervalent iodine(III) reagents as safe alternatives to alpha-nitro-alpha-diazocarbonyls

A cyclopropanation reaction involving iodonium ylides generated in situ allows for efficient preparation of substituted 1-nitro-1-carbonyl cyclopropanes. This robust cyclopropanation reaction can be performed in organic solvents, biphasic aqueous media, or under solvent-free conditions with alkene substrates. The iodonium ylides generated in situ display some surprising differences in reactivity when compared to alpha-nitro-alpha-diazocarbonyl compounds. They do not undergo O-H insertion reactions and exhibit reduced reactivity with certain alkenes. [reaction: see text]     

Water clusters in supramolecular inclusion hydrates. Crystal structure of decaazatricyclo[28.2.2.213.16]tetratriacontane nanohydrate

Inclusion compounds of solvate water molecules in a crystal matrix are investigated by X-ray diffraction analysis of a macrocyclic polyamine decaazatricyclo[28.2.2.2^13.16]tetratriacontane nanohydrate (I). When included in a crystal, water molecules are bonded by water-water (O-H...O) and water—macrocycle (0-H...N and N-H...O) hydrogen bonds, forming a linear cluster. Translated fromZhurnal Strukturnoi Khimii, Vol. 40, No. 5, pp. 993–1001, September–October, 1999.     

Linear free energy correlation analysis on the electronic effects of Rh(II) carbene O-H insertion

The relative rate constants for the Rh(II)-catalyzed insertion of diazoacetone into the O-H bond have been measured through intermolecular competitions. The kinetic data were subjected to Hammett correlation analysis, and mechanistic implication of the results with respect to a stepwise vs a concerted O-H insertion pathway is discussed.     

CpRu-catalyzed O-H insertion and condensation reactions of α-diazocarbonyl compounds

[CpRu(CH(3)CN)(3)][PF(6)] and diimine ligands catalyze together the decomposition of α-diazocarbonyl compounds leading to O-H insertion and condensation reactions. In comparison with Rh(II) and Cu(I) complexes, the CpRu catalysts produce rapid and often more selective reactions. Promising enantioselectivities are obtained in dioxole syntheses.     

Structure and photochemistry of 18-diazo-1,4,7,10,13,16-hexaoxacyclononadeca-17,19-dione and its sodium and potassium complexes. Control of the ground-state conformation of 2-diazo-1,3-dicarbonyl fragment via host-guest complexation

[reaction: see text] The macrocyclic 18-diazo-1,4,7,10,13,16-hexaoxacyclononadeca-17,19-dione (3-diazo-2,4-dioxo-19-crown-6, 1) readily forms complexes with potassium (2, stability constant in methanol is K(K+) = 229 +/- 25 M(-1)) and sodium ions (3, K(Na+) = 84.2 +/- 7.9 M(-1) in methanol). According to B3LYP/6-31G+(d,p) calculations and temperature-dependent 1H NMR spectroscopy, the predominant conformation of 1 has a Z,Z arrangement of the diazo and carbonyl groups. The X-ray crystal structure analysis showed that the potassium complex (2) has the same Z,Z arrangement, while the sodium analogue (2) exists in conformation with Z,E geometry of the diazodicarbonyl moiety. Direct 254 nm photolysis of diazo compounds 1-3 in methanol results in the formation of 3-methoxy-2,4-dioxo-19-crown-6 (5), the product of the insertion of corresponding alpha,alpha'-dicarbonylcarbene into the O-H bond of the solvent. The triplet-sensitized photolysis of diazomalonates 1-3 produces 2,4-dioxo-19-crown-6 (6), which is apparently formed via the triplet state of the intervening carbene.     

Enantioselective copper-catalyzed intramolecular O-H insertion: an efficient approach to chiral 2-carboxy cyclic ethers

A copper-catalyzed asymmetric intramolecular O-H insertion of ω-hydroxy-α-diazoesters has been accomplished by using chiral spiro bisoxazoline ligands. This highly enantioselective intramolecular O-H insertion reaction provides an efficient approach to a variety of synthetically important chiral 2-carboxy cyclic ethers with different ring sizes as well as substitution patterns.     

Synthesis of oxygen-containing heterocyclic compounds based on the intramolecular O-H insertion and Wolff rearrangement of α-diazocarbonyl compounds

The addition products of Ti(IV)-enolate derived from β-keto α-diazo carbonyl compound to ketones or α,β-unsaturated compounds were subjected to Rh₂(OAc)₄-catalyzed and photo-induced diazo decomposition. The Rh₂(OAc)₄-catalyzed reaction afforded intramolecular O-H insertion products, while the photo-induced reaction gave Wolff rearrangement/intramolecular nucleophilic addition products. The transformations represent new approaches to tetrahydrofuran and γ-butyrolactone derivatives.     

Insertion of O-H Bond of Rh(Ⅱ)-methylene Carbene into Alcohols: A Stepwise Mechanism More Plausible than a Concerted Mechanism

The mechanisms of insertion of O-H bond of Rh( Ⅱ ) -methylene carbene into methanol and ethanol were studied by using B3LYP functional both in gas phase and in CH2Cl2. The formation of free alcoholic oxonium ylides is found to be impossible. Alcoholic oxonium ylide are formed as the intermediates before both the stepwise and the concerted transition states of insertion of O-H bond of Rh( Ⅱ ) -methylene carbene into methanol and ethanol. With regard to the mechanisms of insertion of O-H of Rh( Ⅱ ) -methylene carbene into alcohols, analysis of the energy barriers of the two mechanisms indicate that the stepwise mechanism is more plausible than the concerted mechanism.     

Enantioselective carbenoid insertion into phenolic O-H bonds with a chiral copper(I) imidazoindolephosphine complex

The enantioselective O-H carbenoid insertion reaction with a new chiral copper(I) imidazoindolephosphine complex has been developed. The chiral copper(I) complex catalyzed the insertion of carbenoids derived from α-diazopropionates into the O-H bonds of various phenol derivatives to give the corresponding α-aryloxypropionates with up to 91% ee.     

含四硫富瓦烯大环化合物的合成与研究进展

简要介绍了含有四硫富瓦烯(TTF)单元的大环化合物的分类, 概括了各类含四硫富瓦烯大环化合物的合成方法, 主要包括含有1,3-二硫杂环戊烯-2-硫酮单元的大环化合物在亚磷酸三烷基酯参与下的偶合反应, 以及带有氰乙基硫等取代基的预先合成的官能化TTF与二卤代低聚醚的反应. 综述了含四硫富瓦烯大环化合物的电化学性能及其在分子识别方面应用研究的最新进展, 提出了含四硫富瓦烯大环化合物的发展趋势.     

Novel insertion reactions into cyclic tin-oxygen compounds

A series of novel insertion reactions of cyclic carbonyl compounds into cyclic tinoxygen compounds is described. Cyclic carboxycarbonate (1) and isatoic anhydride (4) react with cyclic stannoxane (2) to give the acyclic diester (3) and diamide (5) respectively. Cyclic anhydrides derived from aspartic and glutamic acids (6, 7, 10 and 11) react with 2 to give the macrocyclic tetralactones (8) and (9), and dilactones (12) and (13) respectively. These reactions may be of general synthetic value because of their high specificity. They lead either to singly acylated, acyclic products (3 and 5), or to regiospecific macrocyclic products (8, 9, 12 and 13) in preference to oligomers. The high specificity of these reactions is attributed to: (i) the dual function of the tin element, which may act either as activating group or as protecting group, and (ii) the occurrence of non-covalent transannular interactions between tin and oxygen in the cyclic stannoxane 2.     

Facile chemoselective rhodium carbenoid N-H insertion reactions: synthesis of 3-arylamino- or 3-heteroarylpiperidin-2-ones

Rhodium(II) acetate catalyzed reactions of various substituted 3-diazopiperidin-2-ones with a range of aromatic amines, indoles, and benzotriazole yield exclusively the corresponding N-H insertion products despite competing C-H or O-H insertions. This strategy provides an example of a facile chemoselective N-H insertion reaction delivering a library of 3-arylamino and 3-heteroarylpiperidin-2-one derivatives in high yields.     

One-pot synthesis of N-methylindoles from N-methylanilines and of benzofurans from phenols using transition-metal carbene X-H insertion reactions

Transition-metal carbene X-H insertion reactions (X=N or O) have been employed in the simple conversion of anilines and phenols into indoles and benzofurans, respectively. Thus copper(II) catalyzed N-H insertion reactions of α-diazo-β-ketoesters with N-methylanilines followed by treatment with acidic ion-exchange resin gives indoles. In a similar manner, dirhodium(II) catalyzed O-H insertion reactions of α-diazo-β-ketoesters with phenols followed by treatment with PPA gives benzofurans.     

Three-carbon ring expansion by cyclopropane insertion: macrocyclic musks from readily available C-12 starting materials

A thermal three-carbon ring expansion based on side chain ring insertion of a cyclopropane moiety is described. Flash vacuum pyrolysis (FVP) of 1-cyclopropyl-cycloalk-3-enol derivatives leads to the three-carbon ring expanded enones with clean retention of double bond geometry. Substrates bearing methyl groups on the cyclopropane ring undergo regioselective bond cleavage, allowing for the systematic preparation of selectively substituted macrocyclic musks from low-priced C-12 starting compounds.     

Three-component reaction of aryl diazoacetates, alcohols, and aldehydes (or imines): evidence of alcoholic oxonium ylide intermediates

The Rh(II)-catalyzed three-component reaction of aryl diazoacetates, alcohols and aldehydes was explored, which provided evidence of alcoholic oxonium ylide formation for O-H insertion. A new C-C bond formation reaction where alcoholic oxonium ylides were trapped by electron-deficient aryl aldehydes (or imines) was realized.     

Complexation properties of macrocyclic polyether-diester compounds containing furan and benzene subcyclic units

A new series of macrocyclic polyether-diester ligands containing a furan subcyclic unit is reported. In contrast to other macrocyclic ligands, the twenty-four membered ring diester compounds containing either a furan or benzene subcyclic unit complex more strongly with benzylammonium perchlorate than do the eighteen membered ring compounds.     

Distribution of photo-cross-linked products from 3-aryl-3-trifluoromethyldiazirines and alcohols

The photolysis of N-[4-(3-trifluoromethyl-3H-diazirin-3-yl)benzoyl]-2,2′-ethylenedioxybis(ethylamine) (1) in EtOH, PrOH, i-PrOH, BuOH, and i-BuOH was carried out in both solution (at room temperature) and solid phase (at −196 °C), and the resultant C-H and O-H insertion products were analyzed semi-quantitatively by LC/ESI-MS/MS. The carbene insertion reactions at low temperature produced all possible C-H and O-H insertion products in a relatively uniform distribution, which could not be accomplished by the solution-phase reaction.