Earth-Abundant 3d Transition Metal Catalysts for Hydroalkoxylation and Hydroamination of Unactivated Alkenes

This review summarizes the most noteworthy achievements in the field of C–O and C–N bond formation by hydroalkoxylation and hydroamination reactions on unactivated alkenes (including 1,2- and 1,3-dienes) promoted by earth-abundant 3d transition metal catalysts based on manganese, iron, cobalt, nickel, copper and zinc. The relevant literature from 2012 until early 2021 has been covered.

Isoxazole Strategy for the Synthesis of 2,2'-Bipyridine Ligands: Symmetrical and Unsymmetrical 6,6'-Binicotinates, 2,2'-Bipyridine-5-carboxylates, and Their Metal Complexes

An effective strategy was developed for the synthesis of new 2,2'-bipyridine ligands, symmetrical and unsymmetrical 6,6'-binicotinates, and 2,2'-bipyridine-5-carboxylates, from 4-propargylisoxazoles. The synthesis of symmetrical 2,2'-disubstituted 6,6'-binicotinates was achieved using the Eglinton reaction of 5-methoxy-4-(prop-2-yn-1-yl)isoxazoles with Cu(OAc)₂, followed by Fe(NTf₂)₂/Au(NTf₂) tBuXPhos-catalyzed isomerization of the so-formed mixture of isoxazole/azirine-substituted biacetylenic intermediates. Unsymmetrical 2,2'-disubstituted 6,6'-binicotinates were prepared via a copper-free Sonogashira coupling of 5-methoxy-4-(prop-2-yn-1-yl)isoxazoles with 6-bromonicotinates to give methyl 6-(3-(5-methoxyisoxazol-4-yl)prop-1-ynyl)pyridine-3-carboxylates, followed by a transformation of the propargylisoxazole moiety of the adduct into the pyridine fragment under Fe(II)/Au(I) relay catalysis conditions. 6-(Pyrid-2-yl)nicotinates were synthesized by a Stille-type coupling of 2-(tributylstannyl)pyridine with 6-bromonicotinates. Several cyclopalladated complexes of a new series of 6,6'-binicotinates and 2,2'-bipyridine-5-carboxylates and the homoleptic Cu(I) complex were synthesized in high yields.

Regioselectivity inversion tuned by iron(iii) salts in palladium-catalyzed carbonylations

We disclose the Pd-catalyzed carbonylation of alkenes and alcohols, with the regioselectivity tuned by the anion of Fe(iii) salts.

First-Row Late Transition Metals for Catalytic Alkene Hydrofunctionalisation: Recent Advances in C-N, C-O and C-P Bond Formation

This review provides an outline of the most noteworthy achievements in the area of C-N, C-O and C-P bond formation by hydroamination, hydroalkoxylation, hydrophosphination, hydrophosphonylation or hydrophosphinylation reaction on unactivated alkenes (including 1,2- and 1,3-dienes) promoted by first-row late transition metal catalytic systems based on manganese, iron, cobalt, nickel, copper and zinc. The relevant literature from 2009 until mid-2017 has been covered.

Recent developments in alkene hydro-functionalisation promoted by homogeneous catalysts based on earth abundant elements: formation of C-N, C-O and C-P bond

This Perspective article provides an overview of the recent advancements in the field of intra- and inter-molecular C-N, C-O and C-P bond formation by hydroamination, hydroalkoxylation, hydrophosphination, hydrophosphonylation or hydrophosphinylation of unactivated alkenes, including allenes, 1,3-dienes and strained alkenes, promoted by (chiral) homogeneous catalysts based on earth abundant elements of the s and p blocks, the first row transition metals and the rare-earth metals. The relevant literature from 2009 until late 2014 has been covered.

New Ag(I)-iminophosphorane coordination polymers as efficient catalysts precursors for the MW-assisted Meyer-Schuster rearrangement of propargylic alcohols in water

Treatment of the N-thiophosphorylated iminophosphorane ligands (PTA)═NP(═S)(OR)2 [PTA = 1,3,5-triaza-7-phosphaadamantane, 3a and 3b] and (DAPTA)═NP(═S)(OR)2 [DAPTA = 3,7-diacetyl-1,3,7-triaza-5-bicyclo[3.3.1]nonane, 4a and 4b] with an equimolecular amount of AgSbF6 leads to high-yield formation of the new one-dimensional coordination polymers [Ag{μ(2)-N,S-(PTA)═NP(═S)(OR)2}]x[SbF6]x (5a and 5b) and [Ag{μ(2)-O,S-(DAPTA)═NP(═S)(OR)2}]x[SbF6]x (6a and 6b), respectively. These new (iminophosphorane)silver(I) coordination polymers are efficient catalyst precursors for the Meyer-Schuster isomerization of both terminal and internal alkynols. Reactions proceeded in water, under aerobic conditions and using microwave irradiation as heating source, to afford the corresponding α,β-unsaturated carbonyl compounds in excellent yields, without the addition of any cocatalyst. Remarkably, it should be noted that this catalytic system can be recycled up to 10 consecutive runs (1st cycle 45 min, 99%; 10th cycle 6 h, 97%). ESI-MS analysis of 5a in water has been carried out providing valuable insight into the monomeric active species responsible for catalytic activity in water.

Regio- and diastereoselective synthesis of β-lactam-triazole hybrids via Passerini/CuAAC sequence

Passerini (P-3CR) and Passerini-Smiles reactions were investigated in azetidine-2,3-diones, affording the corresponding 3,3-disubstituted-β-lactams with complete diastereoselectivity in high yields. The study has been carried out using different isocyanides, carboxylic acids, and phenols showing the scope of both reactions. In addition, the regioselective synthesis of highly functionalized β-lactam-triazole hybrids has been developed via a Passerini/CuAAC sequence. Interestingly, the use of dialkynes/diazides or trialkynes/triazides as linkers in the CuAAC step has allowed the synthesis of C(2) and C(3) symmetric β-lactam-triazole hybrids, respectively.