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Aminocyclopropanes, bicyclic

A widely applicable access to bicyclic aminocyclopropanes was outlined by Vilsmaier and coworkers " " on the basis of enaminosulfonium salts. A sulfonium group... [Pg.1373]

J.K. Cha et al. developed a stereocontrolled synthesis of bicyclo[5.3.0]decan-3-ones from readily available acyclic substrates. Acyclic olefin-tethered amides were first subjected to the intramolecular Kulinkovich reaction to prepare bicyclic aminocyclopropanes. This was followed by a tandem ring-expansion-cyclization sequence triggered by aerobic oxidation. The reactive intermediates in this tandem process were aminium radicals (radical cations). The p-anisidine group was chosen to lower the amine oxidation potential. This substituent was crucial for the generation of the aminium radical (if Ar = phenyl, the ring aerobic oxidation is not feasible). [Pg.257]

While intermolecular Kulinkovich-de Meijere reaction assembles cyclopropylamine, many have taken advantage of a pendent olefin at the substrates to synthesize bicycles. Cha converted olefinyl amide 51 to bicyclic amine 52 in excellent yields. Six and co-workers prepared eight bicyclic aminocyclopropanes including 54 (from substrate 53) with yields ranging from 26 to 87%. ... [Pg.21]

Versions of these aminocyclopropanations of terminal alkenes can also be applied intramolecularly. Terminally ethenyl-substituted N,N-dialkylcarboxamides such as 67 yield l-(dialkylamino)bicyclo[n.l.O]alkanes such as 68, while (w-alkenylamino)carboxa-mides such as 69 and 71 lead to 1 -alkyl-2-azabicyclo u.l.0]alkanes such as 70 and 72 (Scheme 11.20) [86,118], and N-allylamino acid N,N-dialkylamides furnish bicyclic diamines (see below). [Pg.415]

Cha s group [89] has recently developed a convenient method for the ring opening of tertiary aminocyclopropane tethered with an alkenyl moiety 199. The PET reaction of 199 led to formation of the five-membered bicyclic system 200 through a [3 + 2] annulation reaction in a good yield, as shown in Scheme 8.55. [Pg.270]

The Beckmann rearrangement also allowed the preparation of cyclopropyl-amines 183-189 yy accessible in 68-77 % yield from the reaction of the oxime (76) with tosyl chloride in dioxane or with trifluoroacetic anhydride in dimethoxy-ethane (equation 13). Bicyclic- and tricyclic aminocyclopropanes (79 and 81) could be obtained from ketones (78 and 80) and hydroxylaminic reagents (equations 14 and 15). Further examples are reported in Refs 188a-j. [Pg.1351]

Hydride as a nucleophile converted 241 into the aminocyclopropanes 244 in fair yields. Here, a ring-opening reaction was prevented by removal of the acceptor carbonyl group in 242 by reduction (Scheme 6). A [2.1.0]-bicyclic system was accessible by this sequence too. [Pg.1373]

Various bicyclic compounds with an aminocyclopropane structural unit (azaquadricyclanes , azabarbaralanes or azaprismanes " ) were obtained by photochemical cyclization of suitable precursors with CC double bonds (e.g. 363 364)... [Pg.1386]

In general, the behavior of the amino moiety in 1 showed no great differences from that of alkylamines or other cycloalkylamines. Cyclopropylamine (77) (pK = 9.10 ) was found to be somewhat less basic than isopropylamine (pK = 10.67 ) further pK values for 77 and other aminocyclopropane derivatives are reported in Refs 347,483 486. Interactions of 77 with p-fluorophenol , propane-2-thiol , H in the presence of 18 crown-6 or Ag have been investigated. For considerations of the protonation of 77 in the gas phase see Refs 491-493. Different basicity was observed for NR2 groups in the exo and endo-posiiion of a [3.1.0] bicyclic system . [Pg.1395]


See other pages where Aminocyclopropanes, bicyclic is mentioned: [Pg.994]    [Pg.1363]    [Pg.1213]    [Pg.994]    [Pg.994]    [Pg.1363]    [Pg.1213]    [Pg.994]    [Pg.794]    [Pg.994]    [Pg.1381]    [Pg.2032]    [Pg.2038]    [Pg.794]    [Pg.994]   
See also in sourсe #XX -- [ Pg.257 ]




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Aminocyclopropanes

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