Restricted Rotation in Aryl Olefins. VI. Substituted β-(2,7-Dimethoxy-1-naphthyl)-α-methylacrylic Acids¹

Abstract

Failure to resolve the aryl olefins II, III, IV and V was reported in the preceding paper.1 Compound I, on the other hand, was resolved2 and an active form had a half-life period of 173 minutes in ra-butanol at 44°. The difference between I and

peri Interaction in Naphthalene Derivatives

“…While the diol is formed only in 14% yield, the oxidation proceeds smoothly to give the ketone in 81% (379). 6 The order of abundance of (5) In this paper (379) the melting point of this ketone is reported to be >300°; no reference is however made to an earlier synthesis of this ketone by Knapp (340) who reports rap 350°dec. Knapp has also reported a few more derivatives of XXXIII.…”

“…In an entirely planar model, the nonbonded -• 0 distance will be ~0. 5 A as against the normal distance of 2.7 A. The serious interaction that would result from such an arrangement is avoided as follows: (i) the nitro groups are rotated about the C-N axis by 45°in one direction, (ii) the C-N bonds undergo a splaying apart to increase the N • • • N distance to 2.93 A from 2.42 A in a hypothetically planar model, (iii) the C-N bonds deviate from the aromatic plane by 0.37 A in opposite directions, and (iv) the carbon atoms bearing the nitro groups are also forced out of the plane of the molecule in the direction of the substituents resulting in slight nuclear distortion (9).…”

A novel type of banana liquid crystals based on 1-substituted naphthalene-2,7-diol cores

“…Oximation of aldehyde 2 with hydroxylamine was followed by dehydration of the intermediate oxime with acetic anhydride to give the corresponding nitrile 3. 25 Deprotection with boron tribromide proceeded very slowly, however, 1c was finally obtained in 55% overall yield. Chlorination of 1a was accomplished 26 by N-chlorosuccinimide in pyridine and the 1-chloro derivative 1d was obtained in 49% yield.…”

“…To a solution of 2,7-dimethoxynaphthalene-1-carbonitrile 25 3 (6.72 g; 0.032 mol) in dry dichloromethane (200 mL), boron tribromide (75 ml of 2 M solution; 0.150 mol) in dichloromethane was added and the mixture was refluxed for 80 h. The deposited crude product was filtered off, washed thoroughly with water and dried. Column chromatography (silica gel, elution with chloroform-methanol (95/5)) afforded pure nitrile 1c, mp 300-303 uC.…”

Axially chiral alkenes: Atroposelective synthesis and applications

“…Adams then investigated a series of bulky aryl olefins to elucidate the relationship between the steric properties of the molecules and their stability to rotation by comparing the half-lives (Fig. 4, compounds 9-26) [19][20][21][22][23][24][25][26][27][28]. While these works constitute a pivotal groundwork in the synthesis of axially chiral olefins, the asymmetric synthesis has remained unattained for half a century since the restricted rotation of these molecules was first observed.…”