O⁽⁻⁾⋯C interactions and bond formation in 1-naphtholate anions with peri-located electrophilic carbon centres

Abstract

n–π* interactions between naphtholate O anions and carbonyl groups are determined to be shorter than in corresponding naphthols by X-ray crystallography, and lead to cyclisations with long O–C bonds when the carbonyl group is replaced by a strongly electron deficient alkene.

Incipient Nucleophilic Attack on a Carbonyl Group Adjacent to a Stereogenic Centre in Peri Naphthalene Derivatives

“…The hydroxy analogue 6 shows a O⋅⋅⋅C(=O) separation of 2.631(2) Å, slightly longer than in similar naphthalenes with peri HO⋅⋅⋅C=O interactions (2.607(3)–2.623(3) Å) involving acetyl or benzoyl groups, 12 and 13 ( Figure 4). [44] The disposition of the carbonyl group is a little different from that in the dimethylamino series and also in the hydroxy naphthalenes 12 and 13 : the torsion of the carbonyl group with respect to the naphthalene ring is reduced to 54.2(2)° compared to 64.14(16) to 77.50(19)° for 7 – 9 , and 62.7 to 71.7° for 12 and 13 . This leads to a widening of the O⋅⋅⋅C=O angle to 118.56(14)°.…”

Mapping of N−C Bond Formation from a Series of Crystalline Peri‐Substituted Naphthalenes by Charge Density and Solid‐State NMR Methodologies

“…[4] These peri-naphthalene systems can alternatively contain methylthio or naphtholate moieties as electron-rich groups,a nd alkynes,p olarized alkenes or aldehydes as the electron-deficient centre. [5,6] Forp eri-naphthalenes bearing adimethylamino (-NMe 2 )group adjacent to an electrophilic group containing amultiple bond (such as C= O, C=C, or CN), the naphthalene skeleton can hold the groups close to the optimal orientation for orbital overlap, often referred to as the Bürgi-Dunitz angle,inducing an n-p* interaction which can modify the chemistry of the groups. [4] If the electrophile is sufficiently reactive an intramolecular bond is formed.…”

Modelling of an aza-Michael reaction from crystalline naphthalene derivatives containing peri–peri interactions: very long N–C bonds?

“…7 The naphthalene framework has been used for observing interactions and reactions between pairs of groups placed at the peri-positions by crystallographic and solid-state NMR methods. 8 Apart from nucleophile/electrophile interactions, peri-substituted naphthalenes have provided chiral hydrocarbons with very large steric interactions, 9 frustrated lone pairs systems 10 and proton sponges, 11 with experimental charge density studies carried out in selected cases. 12 Attractive interactions between functional groups were first reported in the pioneering work from Dunitz et al on the interactions of nucleophiles with carbonyl groups as in naphthalene 1.…”