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Retro Diels-Alder cleavage

Copyright 2013 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. [Pg.143]

Turecek, F. Hanus, V. Charge Distribution Between Formally Identical Fragments the Retro-Diels-Alder Cleavage. Org. Mass Spectrom. 1980, 75, 4-7. [Pg.325]

Actually, the earliest derivative of a vinylcyclopropane radical cation was a serendipitous discovery. It was formed by an unusual hydrogen shift upon photo-induced electron transfer oxidation of tricyclo[4.1.0.0 ]heptane (26). This result has been questioned on the grounds that the same rearrangement was not observed in a Freon matrix. However, there is no basis for the assumption that radical cation reactions in frozen matrices at cryogenic temperatures should follow the same course as those at room temperature in fluid solution and in the presence of a radical anion, which is potentially a strong base. In several cases, matrix reactions have taken a decidedly different course from those in solution. For example, radiolysis of 8 in a Freon matrix generated the bicyclo[3.2.0]hepta-2,6-diene radical cation (27 ), or caused retro-Diels-Alder cleavage yet, the... [Pg.285]

Mass-spectral fragmentation of 5 -steroidal 1-enes, including a quasi-thermal retro-Diels-Alder cleavage... [Pg.223]

Alder-Rickert (retro Diels-Alder) cleavage of the formal cyclopropene adduct 58 (prepared by cycloaddition between norcaradiene and dimethyl acetylenedicarboxylate)... [Pg.1238]

The second route, attributable to Priestley and Warrener, involved the retro-Diels-Alder cleavage (Eq. 5) of the postulated dihydropyridazine 15 (formed in situ by the cycloaddition/elimination shown) under very mild... [Pg.347]

Most of the pyridooxadiazines and pyridothiadiazines possess readily identifiable molecular ions. Compounds containing a quaternary pyridine nitrogen with a halide as counterion show a characteristic peak at M+—HX. Fragments most frequently arise from the loss of HCN, CO, HCNO, SO2H, and from combinations thereof. Retro Diels-Alder cleavage can also be a characteristic process <86ZC100>. [Pg.619]

See other pages where Retro Diels-Alder cleavage is mentioned: [Pg.466]    [Pg.401]    [Pg.140]    [Pg.554]    [Pg.60]    [Pg.606]    [Pg.615]    [Pg.289]    [Pg.302]    [Pg.48]    [Pg.223]    [Pg.86]    [Pg.239]    [Pg.606]    [Pg.615]    [Pg.385]    [Pg.57]    [Pg.231]    [Pg.463]    [Pg.226]    [Pg.235]    [Pg.242]    [Pg.290]    [Pg.382]    [Pg.254]    [Pg.275]    [Pg.356]    [Pg.143]    [Pg.231]    [Pg.416]    [Pg.450]   
See also in sourсe #XX -- [ Pg.5 , Pg.9 , Pg.295 , Pg.300 , Pg.634 ]

See also in sourсe #XX -- [ Pg.5 , Pg.9 , Pg.295 , Pg.300 , Pg.634 ]

See also in sourсe #XX -- [ Pg.143 ]



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