Cleavage-rearrangement

In this reaction only 5% of the expected 12a-methyl steroid (19) can be isolated from the mother liquors after ketal cleavage. Rearrangement is undoubtedly due to magnesium halides in solution, since dimethylmagnesium smoothly effects the transformation of (17) to (19). A 41 % overall yield of (19) is obtained in this experiment. ... 

Since poly(oxy-2,6-dimethy1-1,4-phenylene) has exhibited a high tendency to undergo cleavage, rearrangements and to crosslink in the presence of electrophilic reagents,21 our attention has been focused on modification of poly(arylene ether sulfone), 1, and phenoxy resin,4 The active sites in these polymers are the 3-positions of the bisphenol-A repeating units. We will report the extent of... 

Scheme 114 Five-bond-cleavage rearrangement of O-propargyl oximes to P-lactams...

Similarly, the cumyloxenium ion 320 is involved in the acid-catalyzed cleavage rearrangement reaction of cumene hydroperoxide to phenol and acetone [Eq. (4.184)]. 

GAVOMe in which the carbonyl group has been methylated, gave no ESR or CIDEP observations under various conditions. As expected from the above primary triplet photoreduction mechanism, alkylation precludes the photoreduction and the subsequent cleavage rearrangement. 

Endo-skeletal rearrangements also take place with 1,6-enynes, bnt the proposed mechanism is just a variation of the exo-single-cleavage rearrangement. Formed by endo cyclization, bicyclo[4.1.0]hept-4-ene derivatives arise in some cyclizations of 1,6-enynes by proton loss and protodemetalation ofthe endo cyclopropylcarbene. " That is the case from 1,6-enynes tethered as sulfonamides and in the intramolecular cyclization of 1,6-enol ethers with alkynes (equation 40). ... 

HA1-HA2 complex, peptide bond cleavage/ rearrangement to, 343—345 Hantaan virus, heterologous expression investigation of, 3 HBV. See Hepatitis B virus (HBV)... 

Pepdde bond cleavage/rearrangement, to HA]-HA2 complex, 343—345 pEt vectors, 5 Phase information... 

The adducts of 2-chloroethoxycarbene to conjugated dienes are particularly interesting, since vinylcyclopropanols, formed after cleavage, rearrange to give cyclopentenols under mild conditions. ... 

Phenylsulfanyl)imine 5 took part in a very interesting sequence of ring-cleavage rearrangements to yield cyclohexeneacetonitrile 8 when treated with tributyltin hydride. 

The spectra of the s-triazole 4-sulfonylimines differ clearly from those of the pyridine Af-sulfonylimines.131 These latter compounds possess the following four principal fragmentation processes N-S bond cleavage, rearrangement reactions to ionized V-arylimines and azacarbazoles, the loss of hydrogen atom from the molecular ion, and the cleavage a to the S02 group. 

Recently Reported Studies of Organomagnesium Rearrangements Equilibria in Grignard Cyclization-Cleavage Rearrangements... 

The most impressive array of new Grignard cyclization-cleavage rearrangement examples has come from studies on the intermolecular addition of Grignard reagents to alkenes. In 1975, Lehmkuhl and coworkers published extensive descriptions of their work in this area (46, 47). If an allylic Grignard reagent adds to an alkene, the addition product... 

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