68843-97-0Relevant academic research and scientific papers
Deamination Reactions, 42. Addition of Diazocyclopropanes to Carbonyl Compounds
Kirmse, Wolfgang,Hellwig, Georg,Chiem, Pham van
, p. 1511 - 1524 (2007/10/02)
Diazocyclopropanes (6, 38, 57) were generated in equilibrium with cyclopropanediazonium ions by base-induced cleavage of the analogous nitrosoureas in methanol.Efficient trapping of the diazocyclopropanes occurred in dilute solution with a slight excess of carbonyl compounds.The reactivity of the resulting 1-(α-hydroxyalkyl)cyclopropanediazonium ions (10) depended strongly on the α-substituents.Pinacol rearrangements predominated with aldehyde adducts, the migratory aptitudes being H > Ph > CH3.These 1,2-shifts are thought to proceed with inversion at the terminus - the preferred exo-attack of acetaldehyde at 7-diazonorcarane (38) led to the endo-ketone 40.The major product derived from the acetone adduct 22 was the epoxide 26 whose reaction(s) with metanol were also examined.The intramolecular addition of 8-diazobicyclooctan-4-one (57) gave rise to 6-methoxybicyclooct-4-en-1-ol (60).Due to steric constraints, the intermediate 58 underwent exclusive cyclopropyl-allyl transformations (otherwise a minor reaction).
