Acyl Iodides in Organic Synthesis: I. Reactions with Alcohols

Reaction of acyl iodides RC(O)I (R = Me, Ph) with alcohols R'OH (R' = Me, Et, i-Pr, t-Bu, CH₂ = CHCH₂, HCCCH₂) provides in the corresponding organyl iodides R'I. Unlike that 2-chloroethanol and phenol (R' = CH₂CH₂Cl, Ph) react with RC(O)I in the same way as with acyl chlorides yielding esters RCO₂R'. This reaction path occurs partially also with methanol and ethanol.     

Acyl Iodides in Organic Synthesis: II. Reactions with Acyclic and Cyclic Ethers

Reaction of acyl iodides RCOI (R = Me, Ph) was studied with acyclic and cyclic ethers (Et₂O, MeCHCH₂(O), ClCH₂CHCH₂(O), THF, O(CH₂CH₂)₂O, EtOCH₂CH₂OH, EtOCH = CH₂, PhOEt]. The reaction occurred with the rupture of one or two CO bonds furnishing the corresponding iodides and esters.     

Acyl Iodides in Organic Synthesis: IV. Reaction of Acetyl Iodide with Carboxylic Acids

In contrast to acyl chlorides, reactions of acetyl iodide with monocarboxylic acids follow the exchange pattern to give the corresponding acyl iodides and acetic acid. The reaction attracts interest from the preparative viewpoint as a simple and convenient route to acyl iodides. Acetyl iodide reacts with phthalic acid, yielding acetic acid and phthalic anhydride, while the reaction of acetyl iodide with oxalic acid leads to formation of acetic acid, carbon(II) oxide, and molecular iodine.     

Acyl Iodides in Organic Synthesis: V. Reactions with Carboxylic Acid Esters

Acyl iodides react with alkyl, alkenyl, and aralkyl esters derived from saturated, unsaturated, and aromatic mono- and dicarboxylic acids in the absence of a catalyst. The reaction involves cleavage of the OR bond and formation of organic iodide RI (including CH₂=CHI) and one or two symmetric carboxylic acid anhydrides. Phenyl acetate reacts with benzoyl iodide to give acetyl iodide and phenyl benzoate as a result of cleavage of the (O=)C–O bond. The reaction of diethyl fumarate with acetyl iodide is accompanied by cis– trans isomerization to afford maleic anhydride. In the reactions of acetyl iodide with diethyl oxalate and diethyl malonate, CO and CO₂ and CO₂ and polyketene are formed, respectively, in addition to ethyl iodide and acetic anhydride. Ethyl esters of strong organic acids, e.g., ethyl trihaloacetates, failed to react with acyl iodides under analogous conditions.     

带官能团的双有机碘化锌试剂与酰氯的反应研究

探索了带醚键、酯基、羰基的双有机锌试剂的制备及其在CuCN 2LiCl存在下和酰氯的反应,得到了带官能团的二酮类化合物.该方法条件温和,操作简便,产率中等,提供了合成带官能团的长链二酮类化合物的一种简便方法.     

Acyl Iodides in Organic Synthesis. Reaction of Acyl Iodides with <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>-Dimethyl Carboxylic Acid Amides

Acyl iodides RCOI (R = Me, Ph) reacted with N,N-dimethylformamide and N,N-dimethylacetamide Me₂NC(=O)R’ (R’ = H, Me) along two concurrent pathways involving transacylation and cleavage of the Me-N bond. The first pathway leads to the formation of acyl group exchange products, and the second, to the corresponding imides R’CON(Me)COR.     

Acyl iodides in organic synthesis: X. Reactions with triorganylsilanes and triphenylgermane

Reaction of acyl iodides RCOI (R = Me, Ph) with triorganylsilanes R′₂R″SiH in toluene gives 50–60% of the corresponding triorganyliodosilanes R′₂R″SiI. Triethylsilane reacts with the same acyl iodides under solvent-free conditions to afford the corresponding aldehyde and triethyliodosilane as primary products. Triethyliodosilane undergoes subsequent transformations into hexaethyldisiloxane and triethyl(acyloxy)silane Et₃SiOCOR (R = Me, Ph). Reactions of acyl iodides RCOI (R = Me, Ph) with triphenylgermane in the absence of a solvent lead to formation of iodo(triphenyl)germane in more than 90% yield.     

Acyl iodides in organic synthesis: VIII. Reactions with amino acids

Reactions of acyl iodides RCOI (R=Me, Ph) with glycine, β-alanine, and γ-aminobutyric acid were investigated. The reaction proceeded easily at room temperature without solvent involving both functional groups H₂N and COOH. The prevalence of one of the reaction directions depends on the acidity of the amino acid. The more acidic glycine (pК_a 2.4) reacts with RCOI affording mainly N-acylated product, whereas β-alanine (pК _a 3.60) and especially γ-aminobutyric acid (pК_a 4.06) are predominantly involved into exchange iodination furnishing the corresponding aminoacyl iodides.     

Acyl iodides in organic synthesis: XII. Reactions with organosilicon amines

Reactions were investigated between acyl iodides RCOI (R = Me, Ph) and organosilicon amines of two classes: trimethyl(diethylamino)silane, dimethyl-bis(diethylamino)silane, and hexamethyldisilazane on the one hand, and 3-aminopropyl(triorganyl)silanes H₂N(CH₂)₃SiX₃ (X = Et, EtO) on the other hand. The reaction of RCOI with trimethyl(diethylamino)silane Me₃SiNEt₂ occurred with a cleavage of the Si-N bond and the formation of N,N-diethylacet- or -benzamides and trimethyliodosilane separated in a mixture with hexamethyldisiloxane. At the reaction of acyl iodides RCOI (R = Me, Ph) with dimethyl-bis(diethylamino)silane in the ratio 2:1 in benzene solution both Si-N were ruptured leading to the diethylamide of the corresponding acid and dimethyldiiodosilane. The main product of the reaction of acetyl iodide with hexamethyldisilazane at the molar ratio 2:1 was diacetylimide (MeCO)₂NH. This reaction can be recommended as a simple and convenient preparation procedure for diacylimides. The exothermal reaction of the acetyl iodide with 3-aminopropyl(triethyl)- and -(triethoxy)silanes at the molar ratio of the reagents 1:1 without solvent resulted in quaternary ammonium salts, hydroiodides of the corresponding acetylamides I^?MeCON⁺H₂(CH₂)₃SiX₃ (X = Et, OEt).     

Acyl iodides in organic and organoelement chemistry

This review is focused on our and literature data on reactions of acyl iodides RC(O)I with organic (alcohols, ethers, esters, carboxylic acids, amino acids, tertiary amines, nitrogen heterocycles, carbamides, thiocarbamides, and thiols) and organoelement compounds (alkoxy silanes, siloxanes, silylamines, silazanes, silicon-containing amines, and ethynyl silanes, germanes, and stannanes). Photolysis of acyl iodides in arene medium yields a-diketones, products of photochemical Friedel-Crafts acylation and iodination of arenes, and polyarylenation.     

Quantum-chemical investigation of isocyanate reactions with linear methanol associates: IV. Mechanism of autocatalytic reaction of methyl isocyanate with linear methanol associates

It was shown by quantum-chemical method B3LYP/6-311++G(df,p) that in the autocatalytic reaction the molecules of methyl carbamate formed prereaction complexes with the monomer and dimer of methanol. The complexes possess higher electron-donor properties than free alcohol molecules thus increasing the activity of complexes in the reaction with isocyanates. The products of the autocatalytic reaction are new molecules of carbamate and azomethinenol. The conversions occur through concerted asymmetric late transition states. The isomerization of azomethinenols into carbamates is catalyzed by molecules of alcohols and their associates. The autocatalytic reaction of isocyanates with alcohols becomes possible owing to the ability of alcohols to catalyze the mentioned isomerization.     

Acyl iodides in organic synthesis: XI. Unusual N-C bond cleavage in tertiary amines

Acyl iodides reacted with excess primary and secondary amines in a way similar to acyl chlorides, yielding the corresponding carboxylic acid amide and initial amine hydroiodide. Reactions of tertiary amines with acyl iodides were accompanied by cleavage of the N-C bond with formation of the corresponding N,N-di(hydrocarbyl)carboxamide and alkyl iodide. In the presence of excess tertiary amine the latter was converted into quaternary tetra(hydrocarbyl)ammonium iodide.     

Acyl iodides in organic synthesis: IX. Cleavage of the Si-O-C and Si-O-Si moieties

Reactions of acyl iodides RCOI (R = Me, Ph) with organosilicon compounds involve cleavage of the Si-O-C and Si-O-Si fragments. Acetyl iodide reacts with alkyl(alkoxy)silanes with evolution of heat, and cleavage of the Si-O bond results in the formation of oligo-or polysiloxanes, alkyl iodides, and alkyl acetates. 1,3-Diacetoxytetramethyldisiloxane is formed in the reaction of acetyl iodide with dimethoxy(dimethyl)silane. Acyl iodides readily react with 1-ethoxysilatrane to give 1-acyloxysilatranes as a result of cleavage of the C-O bond. The reaction of acetyl iodide with hexaethyldisiloxane yields triethylsilyl acetate and triethyliodosilane, while in the reaction with octamethyltrisiloxane iodo(trimethyl)silane and dimethyl(trimethylsiloxy)silyl acetate are obtained.     

Pd/Light‐Accelerated Atom‐Transfer Carbonylation of Alkyl Iodides: Applications in Multicomponent Coupling Processes Leading to Functionalized Carboxylic Acid Derivatives

The atom‐transfer carbonylation reaction of various alkyl iodides thereby leading to carboxylic acid esters was effectively accelerated by the addition of transition‐metal catalysts under photoirradiation conditions. By using a combined Pd/hν reaction system, vicinal C‐functionalization of alkenes was attained in which α‐substituted iodoalkanes, alkenes, carbon monoxide, and alcohols were coupled to give functionalized esters. When alkenyl alcohols were used as acceptor alkenes, three‐component coupling reactions, which were accompanied by intramolecular esterification, proceeded to give lactones. Pd‐dimer complex [Pd₂(CNMe)₆][PF₆]₂, which is known to undergo homolysis under photoirradiation conditions, worked quite well as a catalyst in these three‐ or four‐component coupling reactions. In this metal/radical hybrid system, both Pd radicals and acyl radicals are key players and a stereochemical study confirmed the carbonylation step proceeded through a radical carbonylation mechanism.     

On the Reactivity of Lanthanide Iodides LnIx (x < 3) Formed in the Reactions of Lanthanide Metals with Iodine

The reduced lanthanide iodides of the composition LnI_x (Ln = Sc, Y, La, Ce, Pr, Gd, Ho, and Er; x < 3) were obtained by the reaction of an excess of the appropriate metal with iodine at high temperatures. The diamagnetism of the Sc, Y, and La derivatives indicates the trivalent state of the metals in these products. In contrast to the diiodides of Nd(II), Dy(II), and Tm(II), the isolated solids do not dissolve in THF, DME, or liquid ammonia. Despite of their insolubility in THF, all these products readily react in this medium with phenol or alcohols to give the corresponding phenoxy‐ or alkoxylanthanide diiodides ROLnI₂(THF)_x (R = Ph, i‐C₃H₇, t‐Bu; x = 2, 3, or 5) in yields up to 55 %. Their interactions with cyclopentadiene in THF afford the complexes CpLnI₂(THF)₃ with yields up to 60 %. From the reaction of LaI_x with 2, 2'‐bipyridine (bipy), the complex LaI₂(bipy)₂(THF)₂ was isolated. Triphenylcarbinol, stilbene, naphthalene, and anthracene are inert towards the obtained substances.     

Effect of the Reactant Ratio on the Kinetics of Methanolysis of Acyl Chlorides

The apparent second-order rate constants for the reaction of methacryloyl chloride with methanol regularly increase on raising the acyl chloride-to-alcohol ratio. The variation of the rate constants is described by the Michaelis-Menten equation, indicating that the process involves initial formation of an associate with a probable structure of charge-transfer complex (CTC). Thermodynamic parameters of the CTC formation and rate constants and activation parameters for the transformation of CTC into the products have been determined.     

Forming Benzylic Iodides via a Nickel Catalyzed Diastereoselective Dearomative Carboiodination Reaction of Indoles

A diastereoselective dearomative carboiodination reaction is reported. We report a novel metal‐catalyzed approach to install reactive secondary benzylic iodides. Utilizing the unique reactivity of nickel, we have expanded the carboiodination reaction to non‐activated aromatic double bonds forming a previously unattainable class of iodides. We also report a broadly applicable method to avoid the use of a metallic reducing agent by utilizing an alkyl phosphite as the ligand. The reaction is thought to proceed through a syn intramolecular carbonickelation across a 2‐substituted indole followed by a diastereoretentive reductive elimination of the carbon?iodine bond. The complex iodinated indolines generated in the reaction were obtained in moderate to good yields and good to excellent diastereoselectivity. The products were easily functionalized by a variety of synthetic methods.     

Expected and unexpected photochemical reactions of acyl iodides

Photolysis of acyl iodides RCOI (R = Me, Me₂CH, Ph) under UV irradiation in toluene environment for 20–55 h proved to be a simple and efficient method of preparation of symmetrical α-diketones RCOCOR. In contrast, the photolysis under the same conditions of acyl iodides RCOI [R = Me(CH₂)₃, Me₃C] did not lead to the formation of the corresponding diacyls, and the reaction products were unexpected 1,1-bis(4-methylphenyl)pentane and a mixture of isomeric 3- and 4-methyl(tert-butyl)benzenes respectively. The most probable mechanism of their formation is the primary photochemical acylation of toluene in the aromatic ring followed by the photochemical reduction of the arising butyl 4-methylphenyl ketone in the case of the valeroyl iodide or the photochemical Norrish type I cleavage of isomeric 3- and 4-methylphenyl (tert-butyl) ketones in event of the pivaloyl iodide. In the photolysis of acetyl iodide (R = Me) in benzene or toluene alongside the diacetyl formation polyarylation process was observed of acylated and iodinated into the aromatic ring solvents with the formation of polymeric products with semiconductor and paramagnetic properties.     

Acyl iodides in organic synthesis. Reaction of acyl iodides with triphenylethoxy- and triphenylhydroxysilane

The reaction of triphenylethoxysilane with acetyl or benzoyl iodide led to the formation of triphenyliodosilane and ethyl ester of the corresponding carboxylic acid. Triphenyliodosilane formed also in the reaction of triphenylsilanol with benzoyl iodide. These reactions comprise the new simplest method of preparation of the triphenyliodosilane (yield over 60%). The reaction product of triphenylhydroxysilane and acetyl iodide is triphenylacetoxysilane. The reactions of the studied acyl iodides with triphenylhydroxysilane is the first example of different regioselectivity of acetyl iodide and benzoyl iodide in reactions with organic and organoelemental compounds.