A hypothesis for conformational restriction in complexes of formyl compounds with boron Lewis acids. Experimental evidence for formyl CH--O and CH--F hydrogen bonds

Corey, E. J.; Rohde, Jeffrey J.; Fischer, Axel; Azimioara, Mihai

doi:10.1016/s0040-4039(96)02248-4

Cited by 86 publications

(44 citation statements)

References 8 publications

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“…One explanation is that the conformational configuration of BF 3 supports a cationic propagating chain. The formyl proton interacts with a BF 3 fluorine forming a complex at closer than the summation of their van der Waals radii as shown in Scheme (A) . This BF 3 ‐H complex shifts the cationic site from the boron‐oxygen to the formyl carbon, Scheme (B).…”

Section: Resultsmentioning

confidence: 99%

“…Interestingly, the only borohalide to produce polymer was BF 3 ‐OEt 2 . Other borohalides were used in an attempt to determine the effect of a decrease in hydrogen bonding to halide, in the order of F > Cl > Br . In any condition where BF 3 was not used, no yield was obtained despite a color change being observed on addition of the borohalide.…”

Section: Resultsmentioning

confidence: 99%

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Stable, High‐Molecular‐Weight Poly(phthalaldehyde)

Schwartz

Phillips

Engler

et al. 2017

J. Polym. Sci. Part A: Polym. Chem.

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Low ceiling temperature, thermodynamically unstable polymers have been troublesome to synthesize and keep stable during storage. In this study, stable poly(phthalaldehyde) has been synthesized with BF 3 -OEt 2 catalyst. The role of BF 3 in the polymerization is described. The interaction of BF 3 with the monomer is described and used to maximize the yield and molecular weight of poly(phthalaldehyde). Various Lewis acids were used to investigate the effect of catalyst acidity on poly(phthalaldehyde) chain growth. In situ nuclear magnetic resonance was used to identify possible interactions formed between BF 3 and phthalaldehyde monomer and polymer. The

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Stable, High‐Molecular‐Weight Poly(phthalaldehyde)

Schwartz

Phillips

Engler

et al. 2017

J. Polym. Sci. Part A: Polym. Chem.

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“…Recent studies in supramolecular chemistry have demonstrated that hydrogen bonds formed by C–H bonds are not necessarily “weak”, and in certain cases are almost as strong as more traditional A–H···A bonds [20]. The C–H hydrogen bonding between the substrate and the catalyst could be of great significance for transition state organization and energy, and is often invoked to rationalize the outcome of various transformations [21–27]. However, until recently C–H hydrogen bond-based interactions have not been employed in rational organic catalyst design, and more traditional A–H hydrogen bond donors such as I–IX (Fig.…”

Section: Reviewmentioning

confidence: 99%

New approaches to organocatalysis based on C–H and C–X bonding for electrophilic substrate activation

Nagorny¹,

Sun²

2016

Beilstein J. Org. Chem.

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Hydrogen bond donor catalysis represents a rapidly growing subfield of organocatalysis. While traditional hydrogen bond donors containing N–H and O–H moieties have been effectively used for electrophile activation, activation based on other types of non-covalent interactions is less common. This mini review highlights recent progress in developing and exploring new organic catalysts for electrophile activation through the formation of C–H hydrogen bonds and C–X halogen bonds.

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“…For example, the complexes of benzaldehydes with BF 3 [27,35] have the phenyl group anti to the BF 3 . For example, the complexes of benzaldehydes with BF 3 [27,35] have the phenyl group anti to the BF 3 .…”

Section: Structure Of Bf 3 Complexesmentioning

confidence: 99%