One-pot conversion of aromatic bromides and aromatics into aromatic nitriles via aryllithiums and their DMF adduct

Various aromatic bromides and iodides were smoothly converted into the corresponding aromatic nitriles in good to moderate yields by the treatment with n-butyllithium and subsequently DMF, followed by treatment with molecular iodine in aq NH₃. The same treatment of typical aromatics and heteroaromatics with n-butyllithium and subsequently DMF, followed by treatment with molecular iodine in aq NH₃ also provided the corresponding aromatic nitriles in good yields. Moreover, the same treatment of aromatic bromides and aromatics with half amount of DIH (1,3-diiodo-5,5-dimethylhydantoin) instead of molecular iodine worked effectively to give the corresponding aromatic nitriles, respectively, in good yields. These reactions are novel and environmentally benign one-pot methods for the preparation of aromatic nitriles from aromatic bromides and aromatics, respectively, through the formation of aryllithiums and their DMF adducts.     

Chemoselective hydrolysis of tert-butyl esters in acetonitrile using molecular iodine as a mild and efficient catalyst

A simple, mild and efficient method for the hydrolysis of tert-butyl esters using molecular iodine as a catalyst is described. Acid labile protecting groups, such as N-Boc, OBn, OAc and double bonds, are compatible under the reaction conditions.     

Oxidative transformation of azides to aryl nitriles using DIB/TBHP: scope and mechanistic insights

Bis(tert-butylperoxy)iodobenzene, generated in situ by the reaction between diacetoxyl iodobenzene (DIB) and tert-butyl hydroperoxide (TBHP), was used in the oxidative transformation of primary azides to nitriles, and secondary azides to ketones.     

Convenient preparation of tert-butyl esters

A general method is presented for the preparation of tert-butyl esters by the gentle warming of the carboxylic acid in the presence of excess of tert-butyl acetoacetate and a catalytic amount of acid. This method generates only low pressures, and is therefore suitable for laboratory scale pressure glassware.     

Direct oxidative conversion of alkyl halides into nitriles with molecular iodine and 1,3-diiodo-5,5-dimethylhydantoin in aq ammonia

Various benzylic halides were smoothly and directly converted into the corresponding aromatic nitriles in high yields using molecular iodine and 1,3-diiodo-5,5-dimethylhydantoin, respectively, in aq ammonia. Similarly, primary alkyl halides were also converted into corresponding nitriles in moderate to good yields using molecular iodine and 1,3-diiodo-5,5-dimethylhydantoin in aq ammonia, although a long reaction time was required. The present reaction is a new method for the preparation of aromatic nitriles from benzylic halides and a new method for the conversion of alkyl halides into corresponding nitriles with retention of the number of carbon atoms.     

Introducing difluoromethylene sulfonamide group via nucleophilic addition of difluoromethylene anion with aromatic aldehydes

A new fluorine-containing synthon, R¹COCF₂SO₂R² (2, R¹, R²=morpholino, piperidino, etc.), was developed for the introduction of difluoromethylene sulfonamide or difluoromethylene group. Under different conditions, 2 reacted readily with aromatic aldehydes to give the corresponding difluoromethylene-containing alcohols or diols in moderate to good yields in the presence of potassium tert-butoxide. Difluoromethylene sulfonamide group was introduced into organic compounds directly for the first time by this method.     

An efficient method for the conversion of aromatic and aliphatic nitriles to the corresponding N-tert-butyl amides: a modified Ritter reaction

Aromatic and aliphatic nitriles react with tert-butyl acetate in the presence of a catalytic amount of sulfuric acid to give the corresponding N-tert-butyl amides in excellent yields.     

Facile, aprotic degradation of η-CpZrCl3·dme by ternary sodium/group 14 tert-butoxides: From η-CpZrCl3·dme back to NaCp in two easy steps

CpZrCl₃·dme was treated with Na[El(O^tBu)₃], El = Ge, Sn, Pb, respectively. The addition of Na[Sn(O^tBu)₃] to CpZrCl₃·dme caused rapid cyclopentadienide loss and the equally rapid appearance of CpSnCl, half of which crystallized as the trinuclear complex {[ZrCl(O^tBu)₃]₂·CpSnCl}. Pristine CpSnCl reacted almost instantly with NaO^tBu to give NaCp and Na[Sn(O^tBu)₃], which co-crystallized as a coordination polymer. Na[Ge(O^tBu)₃] also displaced Cp from zirconium, but with a different product distribution, giving Cp₂Ge, fac-[Ge(μ-^tBuO)₃ZrCl(O^tBu)₂], and ZrCl(O^tBu)₃. By contrast, Na[Pb(O^tBu)₃] only exchanged its tert-butoxide groups with zirconium to furnish CpZr(O^tBu)₃ and PbCl₂. The solid-state structures of {[ZrCl(O^tBu)₃]₂·CpSnCl}, fac-[Ge(μ-^tBuO)₃ZrCl(O^tBu)₂], and {NaCp·Na[Sn(O^tBu)₃]}_n were determined.     

Facile oxidative conversion of alcohols to esters using molecular iodine

A simple, efficient, and high-yield procedure for the oxidative conversion of alcohols to various types of esters and ketones, with molecular iodine and potassium carbonate was successfully carried out.     

A convenient and efficient synthesis of C-carbamoyl-1,2,3-triazoles from alkyl bromide by a one-pot sequential addition: conversion of ester to amide using Zr(Ot-Bu)4

A convenient and efficient one-pot sequence has been developed for the synthesis of C-carbamoyl-1,2,3-triazoles from alkyl bromide using (i) sodium azide, (ii) methyl propiolate and copper iodide, and (iii) amines, zirconium tert-butoxide, and 1-hydroxybenzotriazole, under microwave irradiation. The sequential reactions in one-pot provided the desired C-carbamoyl-1,2,3-triazoles in excellent yields.     

Copper(I) tert-butoxide-promoted stereospecific alkylation of β-hydroxymethylvinylsilanes with alkyl halides

Stereospecific alkylation of (Z)-β-hydroxymethylvinylsilanes proceeded by treatment with copper(I) tert-butoxide and alkyl halides. Tri- and tetra-substituted allylic alcohols were obtained with complete retention of configuration.     

Direct oxidative conversion of alcohols and amines to nitriles with molecular iodine and DIH in aq NH3

Simple and high-yield procedures for the direct oxidative conversion of various primary alcohols, and primary, secondary, and tertiary amines to the corresponding nitriles were successfully carried out with molecular iodine in aq ammonia and 1,3-diiodo-5,5-dimethylhydantoin in aq NH₃, respectively.     

Direct conversion of aldehydes to acyl azides using tert-butyl hypochlorite

A general method, for the direct conversion of aldehydes to acyl azides using tert-butyl hypochlorite and sodium azide is described. The method is simple and occurs under mild conditions.     

Copper(I) tert-butoxide-promoted coupling of o-(1-hydroxyalkyl)arylsilanes with organic halides

Copper(I) tert-butoxide-promoted coupling of arylsilanes possessing a 1-hydroxyalkyl group at the o-position with organic halides proceeded to give disubstituted arenes. The results indicate that an intermediary arylcopper species is formed by aromatic C^sp2-to-O silyl migration.     

Oxidative fragmentation of oxiranes to nitriles with hypervalent iodine(V) reagents in aqueous ammonia

Oxiranes undergo oxidative fragmentation when treated with hypervalent iodine(V) reagents particularly o-iodoxybenzoic acid in aqueous ammonia to give nitriles. The reaction goes via the formation of 1, 2-amino alcohols as intermediates followed by C-C bond cleavage.     

Deprotection of a primary Boc group under basic conditions

Treatment of a primary t-butyl carbamate (Boc) group with excess sodium t-butoxide in slightly wet tetrahydrofuran or 2-methyltetrahydrofuran provides the corresponding primary amine in excellent yield. We believe the reaction proceeds through an isocyanate intermediate.     

Study of the microwave-assisted hydrolysis of nitriles and esters and the implementation of this system in rapid microwave-assisted Pd-catalyzed amination

Microwave-assisted hydrolysis of benzonitriles and methyl benzoates has been studied using a toluene/concd aq KOH two phase system in the presence and absence of phase transfer catalyst. Conditions to allow and avoid smooth hydrolysis could be identified. Based on the latter, the first microwave protocol which allows the rapid Pd-catalyzed amination of aliphatic amines with chlorobenzenes containing sensitive functional groups has been developed.     

Efficient preparation of Ellman’s imines from trifluoromethyl ketones promoted by zirconium(IV) tert-butoxide

An efficient synthesis of chiral N-tert-butanesulfinyl trifluoromethyl ketimines by using zirconium(IV) tert-butoxide is described. Compared to conventional titanium(IV) ethoxide, this protocol gave better result especially for sterically hindered ketones. In addition to the high reactivity, a high degree of enantiopurity of the N-tert-butanesulfinyl group is retained.     

New cascade reactions starting from acetylenic ω-ketoesters: an easy access to electrophilic allenes and to 1,3-bridgehead ketones

Acetylenic ω-ketoesters bearing a three carboncarbon bond spacer reacted smoothly with tetra-n-butylammonium fluoride and with potassium tert-butoxide to afford either electrophilic allenes or 1,3-bridgehead ketones, the latter being potentially useful molecules for the synthesis of biologically active compounds like Garsubellin A and Hispidospermidin.     

A simple one-pot procedure for the direct conversion of alcohols into alkyl nitriles using TsIm

A convenient and efficient one-pot preparation of nitriles from alcohols using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, treatment of alcohols with a mixture of NaCN, TsIm and triethylamine in the presence of catalytic amounts of tetra-n-butylammonium iodide (TBAI) in refluxing DMF furnishes the corresponding alkyl nitriles in good yields. This methodology is highly efficient for various structurally diverse alcohols with selectivity for ROH: 1° > 2° > 3°.