Isosorbide is a competitive starting material for various valuable derivatives by functionalization and/or substitution since it is a renewable and carbon neutral material that is produced on an industrial scale from sorbitol. A set of O-alkyl- or O-arylated beta-iodo ethers has been synthesized from isosorbide. The key step was the iodoetherification of isosorbide-derived glycals with a variety of oxygenated nucleophiles in the presence of N-iodosuccinimide. trans-Iodo ethers and acetate were obtained in good yields and the removal of iodide affords isosorbide derivatives. The usefulness of this new approach is illustrated by the synthesis of a surfactant having a dimer of isosorbide as hydrophilic group and by the preparation of a structurally unusual bicyclic anhydro carbohydrate.

Isoxazolidin-5-one derivatives are important heterocyclic building blocks in organic synthesis.[1] This heterocyclic ring has been used for the elaboration of bioactive compounds such as nucleoside analogues or steroidal compounds.[2] Moreover, isoxazolidin-5-ones are useful precursors of β-amino acids after reductive cleavage of the N-O bond[1] or by making use of the KAHA ligation process, developed by the Bode group.[3]

Herein, palladium-catalyzed Miyaura borylation of 4-bromo-2,4'-bithiazoles followed by Suzuki-Miyaura cross-coupling reaction (named the MBSC process) with (hetero)aryl- and alkenyl halides is reported. This methodology offers rapid access to various 2',4-disubstituted 2,4'-bithiazole features including naturally-occurring 4-alkenylated and 4-pyridinylated 2,4'-bithiazoles. To prove its application, a concise approach for the synthesis of a heterocyclic cluster of the thiopeptide d-series antibiotic GE2270 is reported through a late-stage MBSC strategy.

A straightforward enantiomerically pure synthesis of the heterocyclic core of the D-series GE2270 is reported. The synthetic strategy combines the Hantzsch thiazole's building condensation with a cross-coupling reaction including direct C-H hetarylation to build and connect step-by-step thiazolyl moieties to the 5-bromopicolinate as readily available starting material.

An unprecedented multicomponent organocatalyzed Knoevenagel-aza-Michael-cyclocondensation reaction between Meldrum's acid, hydroxylamines, and aldehydes afforded a straightforward entry to a large array of racemic and syn-diastereoenriched isoxazolidinones as synthetically useful scaffolds. This process revealed a markedly facile aza-Michael-cyclocondensation sequence as a key domino reaction between RCO2NHOH and transient alkylidene Meldrum's acid upon Brønsted base catalysis.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Various pyrazolidinones can be obtained by the direct synthesis between Meldrums acid and azomethine imines (II) or through a novel multicomponent reaction between the acid, aldehydes, and pyrazolidinones.

A practical sequence for the synthesis of optically active heteroaryl α-(hydroxyamino) esters was explored. The highly diastereoselective addition of heteroaromatics to a cyclic chiral nitrone allowed access to a series of heteroaryl hydroxylamines. The scope of this reaction was evaluated on substrates possessing a pyrrole, an indole, or a furan core. The three-step sequence afforded the α-(hydroxyamino) esters in good overall yields (36–62 %) with good enantiomeric excess values (76 to ≥98 %).

We discovered a novel organocatalysed multicomponent domino Knoevenagel-aza-Michael-cyclocondensation reaction leading to an unprecedented straightforward synthesis of 1,5-diazabicyclo[3.3.0]octane-2,6-diones. The specific capability of the (DHQ)2PHAL organocatalyst in this process was also highlighted to eventually furnish the corresponding bicyclopyrazolidinones with up to 96 : 4 er.

This method gives access to substituted isosorbide derivatives which can be further functionalized.

AbstractThe use of an in situ generated N‐heterocyclic carbene allows for the synthesis of a variety of tertiary alcohols (III) from secondary alcohols (I) through a domino oxidation—addition protocol.

The use of commercially available (SIPr)Pd(cinnamyl)Cl (SIPr = 1,3-bis(2,6-diisopropylphenyl)-4,5-dihydroimidazol-2-ylidene) as a precatalyst for the anaerobic oxidation of secondary alcohols is described. The use of this complex allows for a drastic reduction in the reaction times and catalyst loading when compared to the unsaturated counterpart. This catalytic system is compatible with the use of microwave dielectric heating, decreasing even further catalyst loading and reaction times. Domino Pd-catalyzed oxidation-arylation reactions of secondary alcohols are also presented.

This chapter highlights the use of N-heterocyclic carbenes as supporting ligands in arylation reactions different than the more common cross-coupling reactions, including C-F bond activation, catalytic arylation, homocoupling, direct arylation and oxidative Heck reactions.

The use of in situ generated (NHC)-Ni catalytic species (NHC = N-heterocyclic carbene) allows for the synthesis, in short reaction times, of a variety of tertiary alcohols from secondary alcohols through a domino oxidation-addition protocol.

A new strategy for the preparation of unsymmetrical 2,2'-bis(pyrrolyl)alkanes has been developed. It involved the condensation of pyrrole derivatives onto N-benzylhydroxylamines in the presence of HCl. This two-step procedure provided access to a wide variety of 2,2'-dipyrromethanes (3a-m). It has also been extended to the synthesis of tripyrromethanes 4a-d and of N-confused dipyrromethanes 6a-d.

The selective, anaerobic catalytic oxidation of secondary alcohols at room temperature by using an in situ (N-heterocyclic carbene)-Ni(0) system is presented. The use of non-anhydrous, non-degassed 2,4-dichlorotoluene as both the oxidant and the solvent allows for very short reaction times and very high yields. In addition, a well-defined (N-heterocyclic carbene)-Ni(0) complex was synthesized and applied to these oxidation reactions.

The stereoselective synthesis of penmacric acid, an optically active C-4 substituted pyroglutamic acid, has been efficiently achieved through an unusual 11-step sequence starting from simple N-triisopropylsilylpyrrole. The key-steps are the initial addition of the pyrrole nucleus onto a chiral nitrone and the obtention of the pyroglutamic acid moiety by reductive hydrogenation of the pyrrole followed by oxidation of the corresponding pyrrolidine into pyrrolidinone.

The use of aryl chlorides as oxidants for the selective oxidation of a variety of secondary alcohols in anaerobic conditions with (NHC)-Pd and -Ni systems (NHC = N-heterocyclic carbene) at very mild temperatures is presented.

Regioselective additions of pyrroles to a variety of optically active nitrones under smooth acidic conditions lead to chiral pyrrolic N-hydroxylamines in good to excellent yields. Depending on the position of the chirality on the nitrone partner, the addition products have been isolated with high diastereoselectivity levels. Reaction of glyoxylate based chiral nitrones either at the C-2 or at the C-3 position of the pyrrole nucleus afforded N-hydroxyamino esters in high yields as single diastereoisomers. These adducts allow access to enantio-enriched non proteinogenic 2'- and 3'-pyrrolylglycines (13 and 19 respectively).