2,2-Dimethylisoindene and 5,5-dimethylbenzobicyclo[2.1.0]pent-2-ene

The photochemistry of the N-oxide function

“…There are then a number of photochemical reactions in which the iV-oxide function plays no special part, such as the electrocyclic rearrangement of azine mono-iV-oxide,42 the sigmatropic rearrangement of 4Hpyrazole iV-oxides,42 and the chelotropic elimination of N20 from cyclic aliphatic azoxy derivatives. 27 The nitrone 33 is photochemically decomposed to benzo-Besides the rearrangement to lactams, fragmentation is also observed. Thus, the benzimidazole iV-oxide 34c, while reacting in the normal way in methanol, yields mainly products 37 and 38 by irradiation in dioxane.…”

“…Indeed, 1,3oxazepines are converted thermally into 2-acylpyrroles only under very drastic conditions87 and they appear to be photochemically stable.85 D. Other Processes Migration of the oxygen to the 3-carbon atom is generally unimportant, an exception being the formation of the imidazole 71 as the main product (34% yield) from 5-methoxypyrimidine 1-oxide.80 Pyridones and analogue derivatives are often formed, particularly from pyrimidine IV-oxides,83-84 but in yield rarely exceeding 10%.5 However, in the case of pyrazine-1,4-dioxide, a double rearrangement of this type takes place, yielding 2,5-dihydroxypyrazine (72).90 73) and isoxazole (74, arising through a retrocyclization from the former). This process has (27) been rationalized as involving initial homolysis of the N-N bond.91-92…”

Convenient syntheses of 5,5,9-trimethyl-trans-1-decalone and 6.beta.-hydroxy-5,5,9.beta.-trimethyl-trans-1-decalone

“…The value of 5,5,9-trimethyl-frans-l-decalone2 (1) and 6/3-hydroxy-5,5,9d-trimethyl-frans-l-decalone (2) as o o synthetic intermediates has been demonstrated in the synthesis of several terpenes. 3 In connection with several (1) Direct correspondence to D.S.W.…”

.sigma.-Naphthoquinodimethanes and .sigma.-phenanthroquinodimethanes. Isoindene-related species

“…In a recent series of papers we examined the generation and the thermal and photochemical behavior of 2,2-dimethylisoindene (1) and other 2-alkyl-2-methylisoindenes (2).1-5 1 was itself able to be isolated either as a gas or 1 2, R = CHjCHj, (CH3)2CH, PhCH2, c-C3H5CH2 in dilute solution, and it was fully characterized spectroscopically, the first time such an o-benzoquinodimethane species had been able to be so fully characterized.2,3 Its NMR spectrum showed complex vinylic absorptions at 6.08 (4 H) and 6.55 (2 H) in addition to a six-proton singlet at 1.16, all consistent with 1 having nonaromatic character.…”