Benzoin Condensation of Anisaldehyde

Sumrell, Gene; Stevens, John I.; Goheen, Gilbert E.

doi:10.1021/jo01352a009

Cited by 12 publications

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“…Reagents and solvents were purchased from Aldrich, Alfa Aesar, Merck or Fisher and used as received unless otherwise noted. Anisoin and 4-methoxybenzoin were prepared according to Sumrell et al [36]. CDCl 3 was distilled from K 2 CO 3 and stored in the dark over 4A molecular sieves.…”

Section: Methodsmentioning

confidence: 99%

Experimental and Theoretical Insight into Electrocatalytic Hydrogen Evolution with Nickel Bis(aryldithiolene) Complexes as Catalysts

Ζαρκαδούλας

Field

Papatriantafyllopoulou

et al. 2015

Inorg. Chem.

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A series of neutral and monoanionic nickel dithiolene complexes with (p-methoxyphenyl)-substituted 1,2-dithiolene ligands have been prepared and characterized with physicochemical methods. Two of the complexes -the monoanion of the symmetric [Ni{S 2 C 2 -(-Ph-p-OCH 3 ) 2 } 2 ] (3 -) with NBu 4 + as a counter-ion and the neutral asymmetric [Ni{S 2 C 2 (-Ph)(-Ph-p-OCH 3 )} 2 ] (2)-have been structurally characterized by single crystal X-ray crystallography. All complexes have been employed as proton reducing catalysts in DMF with trifluoroacetic acid as proton source. The complexes are active catalysts with good faradaic yields reaching 83% for 2 but relatively high overpotentials requirements (0.91 V and 1.55 V measured at the middle of the catalytic wave for two processes observed depending on the different routes of the mechanism). The similarity of the experimental data regardless of whether the neutral or anionic form of the complexes is used indicates that the neutral form acts as pre-catalyst. On the basis of detailed DFT calculations the proposed mechanism reveals two main different routes after the protonation of the dianion of the catalyst in accordance with the experimental data, indicating the role of the concentration of the acid and the influence of the methoxy groups. Protonation at sulfur seems be more favorable than at the metal, which is in marked contrast with the catalytic mechanism proposed for analogous cobalt dithiolene complexes.

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Section: Methodsmentioning

confidence: 99%

Experimental and Theoretical Insight into Electrocatalytic Hydrogen Evolution with Nickel Bis(aryldithiolene) Complexes as Catalysts

Ζαρκαδούλας

Field

Papatriantafyllopoulou

et al. 2015

Inorg. Chem.

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“…Benzoin, p-anisoin, and 4-methoxy-benzoin were prepared according to literature procedures [119], based on the condensation of two benzaldehydes in the presence of cyanide as shown below: Data for these compounds agree with those reported earlier in the literature.…”

Section: Preparation and Characterization Of Ligandssupporting

confidence: 58%

Photocatalytic and electrocatalytic hydrogen production with dithiolene complexes

Ζαρκαδούλας¹

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Η παρούσα διδακτορική διατριβή εκπονήθηκε στο Εργαστήριο Ανόργανης του Εθνικού και Καποδιστριακού Πανεπιστημίου Αθηνών. Περιέχει βιβλιογραφική αναφορά στην εφαρμογή των διθειολενικών συμπλόκων ως καταλύτες στην ηλεκτροκαταλυτική παραγωγή υδρογόνου και μερικά βιομιμητικά υπερμοριακά συστήματα ομογενούς φωτοκαταλυτικής παραγωγής υδρογόνου. Στο πειραματικό μέρος, αναφέρεται η σύνθεση, ο χαρακτηρισμός και η μελέτη δις-διθειολενικών συμπλόκων του νικελίου. Αυτές οι ενώσεις έχουν παραπλήσιες δομικές και ηλεκτρονικές ιδιότητες που μπορούν να ρυθμιστούν ώστε να παρατηρηθούν συσχετισμοί δομής – δραστικότητας. Η πρώτη σειρά συμπλόκων είναι του τύπου [Ni(S2C2–p–C6H5–R)(S2C2–p–C6H5–R′)], όπου R = R′ = H, R = OMe και R′ = H, R = R′ = OMe. Απομονώθηκαν και επιλύθηκαν οι κρυσταλλικές δομές για τις ενώσεις με R = OMe και R′ = H και το μονοανιοντικό σύμπλοκο με τις ομάδες R = R′ = OMe. Η δεύτερη σειρά συμπλόκων περιέχει τα μονοανιοντικά σύμπλοκα (NBu4)[Ni(bdt)2], (NBu4)[Ni(tdt)2] και (NBu4)[Ni(mnt)2], όπου bdt, tdt, and mnt είναι 1,2–βενζοδιθειολάτο, τολουολο–3,4–διθειολάτο, και μαλεονιτριλο-διθειολάτο, αντίστοιχα. Το ετεροληπτικό σύμπλοκο (NBu4)[Ni(S2C2Ph2)(mnt)] παρασκευάστηκε και η κρυσταλλική του δομή επιλύθηκε, όπως επίσης και τα τρία αλκυλιωμένα και γεφυρωμένα σύμπλοκα [Ni(bdt)2C3], [Ni(S2C2Ph2)2C3] και [Ni(S2C2–p–6H4OMe)2C3], όπου C3 είναι γέφυρα της μορφής –CH2CH2CH2–. Όλα τα σύμπλοκα χαρακτηρίστηκαν με φασματοσκοπικές και φυσικοχημικές μεθόδους, όπως η φασματοσκοπία απορρόφησης, η φασματοσκοπία υπερύθρου, η φασματοσκοπία μαγνητικού πυρηνικού συντονισμού και η κυκλική βολταμμετρία. Τα αναφερθέντα σύμπλοκα εφαρμόστηκαν ως καταλύτες αναγωγής πρωτονίων σε οργανικούςδιαλύτες (Ν,Ν′-διμεθυλοφορμαμίδιο και ακετονιτρίλιο) με οργανικά οξέα (τριφθοροξικό οξύ κ.ά.).

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“…Additionally, the coupling constants of the two benzylic hydrobenzoin protons in the substrates 8a-8f are shown as well, following the interpretation model stated in case of the stereoselective reduction of the corresponding phenyl glyoxylates. 1d,11 As can be seen from Table 1 (entries 1 and [3][4][5], the application of an electron poor alkylating agent had a not very significant, but negative, effect on the achievable diastereoselectivities, a larger degree of racemization was observed during saponification of the obtained esters 9f-9g due to the necessity for prolonged reaction times and higher reaction temperatures causing the nitro substituted acids 10b to be obtained in only poor enantiomeric purities. However, especially in the case of the 2-methoxy substituted auxiliaries (see entries 1 and 8), satisfactory diastereomeric ratios were observed; looking at the correlation of de-values and the corresponding coupling constants determined for the benzylic protons of the substrates 8a-8e, an interpretation based on the model proposed by Rosini et al 11 seems obvious (Scheme 4).…”

Section: Evaluation Of Auxiliaries Via Model Reactions In Solution Phasementioning

confidence: 99%

Chiral linker 5: scope and limitations of arylsubstituted m-hydrobenzoins as solid supported open chain chiral auxiliaries for diastereoselective syntheses

Broeker

Knollmueller

Gärtner

2009

Tetrahedron: Asymmetry

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Benzoin Condensation of Anisaldehyde

Cited by 12 publications

References 0 publications

Experimental and Theoretical Insight into Electrocatalytic Hydrogen Evolution with Nickel Bis(aryldithiolene) Complexes as Catalysts

Experimental and Theoretical Insight into Electrocatalytic Hydrogen Evolution with Nickel Bis(aryldithiolene) Complexes as Catalysts

Photocatalytic and electrocatalytic hydrogen production with dithiolene complexes

Chiral linker 5: scope and limitations of arylsubstituted m-hydrobenzoins as solid supported open chain chiral auxiliaries for diastereoselective syntheses

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