Nucleophilic Reactivities of Azulene and Fulvenes

Abstract

Keywords: Carbocations / Aromaticity / Kinetics / Linear free energy relationships / UV/Vis spectroscopy / Nucleophilic additionThe kinetics of the reactions of azulene (1), 6,6-dimethylfulvene (2), 6-[4-(dimethylamino)phenyl]fulvene (3) and 6-(julolidin-9-yl)fulvene (4) with a set of benzhydrylium ions (reference electrophiles) have been investigated in MeCN.The second-order rate constants for these reactions correlate linearly with the electrophilicity parameters (E) of the benzhydrylium ions. According to the linear free-enthalpy rela-

Visible‐Light‐Accelerated C−H Sulfinylation of Heteroarenes

“…The reaction with a methoxy‐substituted thiophene derivative 2 n (product 3 ab ) and the benzene derivatives 2 o and 2 p (products 3 ac and 3 ad ) indicate the limits of the method towards decreasing nucleophilicity and increasing aromaticity of the arene component and give only small product yields. Azulene ( 2 q ) led to a high yield of 88 % for 3 ae owing to its high nucleophilicity (N 6.66) …”

Reaction of Arylnitroso Derivatives: Synthesis of Arylimino 2,5-Dihydrofuran and Arylamino Fulvenes Derivatives

“…These structures are subunit of several bioactive natural and synthetic products [14] [15]. Fulvenes have high relevance as synthons [16] [17] and materials [18]- [24]. This report will provide a fast and easy protocol to execute the preparation of the abovementioned heterocycles cores.…”

Cooperative benzylic–oxyallylic stabilized cations: regioselective construction of α-quaternary centers in ketone-derived compounds

“…While we and others have extensively utilized substituted indoles in studies concerning a direct nucleophilic addition to oxyallyl cations, 4f , 4g , 5 there are only a few precedents on the utility of other carbon and heteroatom nucleophiles in this type of chemistry. 4g , 4h As a guideline for us to judiciously select other potential carbon nucleophiles beyond indole, we consulted Mayr's nucleophilicity parameters ( N values) 13 and extracted the N values of various substituted indoles, which ranged from N = 2.2 for electron poor indoles to N = 7.2 for electron rich indoles, 13 d as a reference. As illustrated in Table 4 , this strategy enabled us to identify that pyrrole ( N = 4.6) successfully reacted with starting materials 19 and 20 to afford the corresponding methylenol ethers 27a and 28a in 45% and 89% yields, respectively, although these reactions were rather sluggish.…”