A method for the synthesis of substituted cycloalkanes was developed using diols and secondary alcohols or ketones via a cascade hydrogen borrowing sequence. A non-noble and air-stable manganese catalyst (2 mol %) was used to perform this transformation. Various substituted 1,5-pentanediols (3–4 equiv) and substituted secondary alcohols (1 equiv) were investigated to prepare a collection of substituted cyclohexanes in a diastereoselective fashion. Similarly, cyclopentane, cyclohexane, and cycloheptane rings were constructed from substituted 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol, and sterically hindered ketones following a (4 + 1), (5 + 1), and (6 + 1) strategy, respectively. This reaction provides an atom economic methodology to construct two C–C bonds at a single carbon center generating high-value cycloalkanes from readily available alcohols as feedstock using an earth-abundant metal catalyst.

Earth-abundant metal complexes have been attracting increasinga ttention in the field of photo(redox)catalysis. In this work, the synthesis and full characterisation of four new heteroleptic Cu I complexes are reported, which can work as photosensitizers. The complexes bear ab ulky diphosphine (DPEPhos = bis[(2-diphenylphosphino)phenyl] ether) and ad iimine chelating ligand based on 1-benzyl-4-(quinol-2'yl)-1,2,3-triazole. Their absorption has ar elative maximum in the visible-light region, up to 450 nm. Thus, their use in photocatalytic systemsf or the reduction of CO 2 with blue light in combination with the known catalyst [Ni II (cyclam)]Cl 2 was tested.T his system produced CO as the main product through visible light (l = 420 nm) with aT ON up to 8a fter 4hours. This value is in line with other photocatalytic systemsu sing the same catalyst. Nevertheless, this system is entirely noble-metal free.

Fully earth‐abundant and highly efficient systems for producing syngas CO/H2 through photocatalytic reduction from CO2 are essential to approach a sustainable way of closing the carbon cycle. Herein, the synthesis and characterization of a new iron complex, FeIIL(NCS)2py, coordinated to an N,N,N‐pincer ligand 2,6‐bis(4’‐phenyl‐1’,2’,3’‐triazol‐1’‐yl‐methyl)pyridine (L), two isothiocyanate groups (NCS) and one pyridine is reported. Its catalytic activity in the photo‐driven reduction of carbon dioxide has been investigated and compared with its CoII analogue (CoL(NCS)2py) and their homoleptic complexes ML2. In this work, the catalysts are used in combination with the heteroleptic complex [CuI(dmp)(DPEphos)], where dmp is 2,9‐dimethyl‐1,10‐phenanthroline and DPEPhos is bis[(2‐diphenylphosphino)phenyl] ether, to reach entirely earth‐abundant systems. The new iron heteroleptic complex FeIIL(NCS)2py showed considerable activity with a TONCO of 576 obtained after 4 h (TOF=144 h−1) through visible light (λ=420 nm) and a quantum yield of 7.1 %.