Financial support of the Spanish Ministry of Science and
Innovation (CTQ2012-38543-C03) and Generalitat Valenciana
(PROMETEO/2012/020) is acknowledged. V.M.-C. thanks the
Spanish Ministry of Science and Education for a predoctoral
fellowship (FPU AP2007-02562) and Generalitat Valenciana for
a VALi+d postdoctoral fellowship (APOSTD/2013/041).
M.D.P. thanks the Spanish Ministry of Education for a
postdoctoral fellowship and UGC India for a Startup Grant.

Macrocyclization Reactions: The Importance of Conformational, Configurational, and Template-Induced Preorganization

Nowadays, the importance of bibliographic databases (DBs) has increased enormously, as they are the main providers of publication metadata and bibliometric indicators universally used both for research assessment practices and for performing daily tasks. Because the reliability of these tasks firstly depends on the data source, all users of the DBs should be able to choose the most suitable one. Web of Science (WoS) and Scopus are the two main bibliographic DBs. The comprehensive evaluation of the DBs’ coverage is practically impossible without extensive bibliometric analyses or literature reviews, but most DBs users do not have bibliometric competence and/or are not willing to invest additional time for such evaluations. Apart from that, the convenience of the DB’s interface, performance, provided impact indicators and additional tools may also influence the users’ choice. The main goal of this work is to provide all of the potential users with an all-inclusive description of the two main bibliographic DBs by gathering the findings that are presented in the most recent literature and information provided by the owners of the DBs at one place. This overview should aid all stakeholders employing publication and citation data in selecting the most suitable DB.

Web of Science (WoS) and Scopus: The Titans of Bibliographic Information in Today’s Academic World

We describe a fully stereodivergent synthesis of a range of α,α-disubstituted α-amino acids via an Ir/Cu-catalyzed α-allylation of readily available imine esters The introduction of a Cu-Phox complex-activated imine ester into the chiral iridium-catalyzed allylic allylation process is crucial for its high reactivity and excellent enantio- and diastereoselectivity (up to >99% ee and >20:1 dr) Importantly, the two chiral catalysts allow for full control over the configuration of the stereocenters, affording all stereoisomers of the desired products The utility of this methodology was demonstrated by synthesizing dipeptides and analogues of bioactive molecules in a stereodivergent manner

Ir/Cu Dual Catalysis: Enantio- and Diastereodivergent Access to α,α-Disubstituted α-Amino Acids Bearing Vicinal Stereocenters

Macrocyclic scaffolds are commonly found in bioactive natural products and pharmaceutical molecules. So far, a large number of macrocyclic natural products have been isolated and synthesized. The construction of macrocycles is generally considered as a crucial and challenging step in the synthesis of macrocyclic natural products. Over the last several decades, numerous efforts have been undertaken toward the synthesis of complex naturally occurring macrocycles and great progresses have been made to advance the field of total synthesis. The commonly used synthetic methodologies toward macrocyclization include macrolactonization, macrolactamization, transition metal-catalyzed cross coupling, ring-closing metathesis, and click reaction, among others. Selected recent examples of macrocyclic synthesis of natural products and druglike macrocycles with significant biological relevance are highlighted in each class. The primary goal of this review is to summarize currently used macrocyclic drugs, highlight the therapeutic potential of this underexplored drug class and outline the general synthetic methodologies for the synthesis of macrocycles.

https://www.mdpi.com/1420-3049/18/6/6230/pdf

Macrocyclic Drugs and Synthetic Methodologies toward Macrocycles

Fully stereodivergent dual-catalytic α-allylation of protected α-amino- and α-hydroxyacetaldehydes is achieved through iridium- and amine-catalyzed substitution of racemic allylic alcohols with chiral enamines generated in situ. The operationally simple method furnishes useful aldehyde building blocks in good yields, more than 99% ee, and with d.r. values greater than 20:1 in some cases. Additionally, the γ,δ-unsaturated products can be further functionalized in a stereodivergent fashion with high selectivity and with preservation of stereochemical integrity at the Cα  position.

Stereodivergent Dual Catalytic α-Allylation of Protected α-Amino- and α-Hydroxyacetaldehydes

Products A. Parenty,† X. Moreau,†,§ Gilles Niel,‡ and J.-M. Campagne*,†,‡ †Institut de Chimie des Substances Naturelles, Avenue de la Terrasse, F-91198 Gif sur Yvette, France Institut Lavoisier de Versailles, UMR CNRS 8180, Universite ́ de Versailles-Saint-Quentin-en-Yvelines, 45 Avenue des Etats-Unis, 78035 Versailles Cedex, France ‡Institut Charles Gerhardt, UMR5253, Ecole Nationale Supeŕieure de Chimie, 8 rue de l’Ecole Normale, F-34296 Montpellier, France

Update 1 of: macrolactonizations in the total synthesis of natural products.

After seminal Tsuji–Trost reactions (palladium catalyzed allylation of nucleophiles via π-allyl intermediates as electrophiles), the idea of reversal reactivity of π-allyl intermediates (i.e. π-allyl as nucleophiles) has been stated since the eighties. Thanks to different transition metal sources and the modification of their electronic environment through the use of additives and ligands, such ‘reactivity switch’ of π-allyl intermediates proved its powerfulness allowing high control in regio-, diastereo- and enantio-selectivities. These methodologies have thus emerged as efficient methods in the catalytic enantioselective allylation of carbonyl compounds and imines with a deep impact on natural product and/or drug elaboration. This tutorial review highlights the concept of ‘umpoled’ reactivity of π-allyl intermediates, relying on selected recent examples.

Catalytic nucleophilic ‘umpoled’ π-allyl reagents

Owing to their significant abundance in natural products, chiral β,β′-disubstituted α-amino acids remain an important synthetic objective. Emphasis has been focused in this critical review on the great diversity of enantio- and diastereoselective methodologies to reach these highly functionalized compounds. The oldest and cutting edge synthetic methods are described in parallel with the synthesis of many relevant biologically active targets (224 references).

Stereocontrolled routes to β,β′-disubstituted α-amino acids

Vinyl-aziridines and cyclopropanes in Pd-catalyzed (3+2)-cycloaddition reactions with cyclic N-sulfonyl imines

A comparative study of the three main chemical information systems (Scifinder, Web of Science and Scopus) was performed by studying the indexing policies of titles, abstracts and keywords within selected literature articles. Various chemical expressions were introduced as topic searches to illustrate the different search tools related to term indexing. The resulting article lists were compared two-by-two by means of a script designed to identify common reference lists and specific ones to each editor. Analyzing these specific reference lists reveals that only partial coverage areas of references should be expected when querying a single platform. The discussion covers the term and keyword indexing policies, their influence on the retrievability of references and on the retrievability of the highly cited papers.

/pdf/chemical-bibliographic-databases-the-influence-of-term-40sd861d8c.pdf

Gilles Niel

Papers

Update 1 of: macrolactonizations in the total synthesis of natural products.

Catalytic nucleophilic ‘umpoled’ π-allyl reagents

Stereocontrolled routes to β,β′-disubstituted α-amino acids

Vinyl-aziridines and cyclopropanes in Pd-catalyzed (3+2)-cycloaddition reactions with cyclic N-sulfonyl imines

Chemical bibliographic databases: the influence of term indexing policies on topic searches