81522-28-3Relevant academic research and scientific papers
Intramolecular Reactivity of Arylcarbenes: Derivatives of o-Tolylcarbene
Kirmse, Wolfgang,Konrad, Wolfgang,Schnitzler, Dirk
, p. 3821 - 3829 (2007/10/02)
Various CH2X groups have been attached to the ortho position of phenylcarbene.If 2'- or 3'-C-H bonds are present, as in 23 (X = Me), 71 (X = CMe3), and 58 (X = SiMe3), C-H insertion leading to five- or six-membered rings predominates in the gas phase and competes with intermolecular reactions in solution.The formation of benzocyclobutenes via insertion into 1'-C-H bonds is a very minor reaction path of 23 and 71.In contrast, 58 produces substantial amounts of the benzocyclobutene 59 by way of C-Si insertion, particularly in the gas phase.Insertion into the Si-Me bonds of 58 also occurs while the C-F bonds of 37 (X = CF3) and 50 (X = F) are inert.In the gas phase, 37 and 50 give mainly benzocyclobutenes whereas intermolecular reactions prevail in solution.The effects of sensitization and of solvent polarity suggest that benzocyclobutenes arise from singlet arylcarbenes.The amount of carbene-carbene rearrangement decreases in the order 7 (X = H) > 37 (X = CF3) > 23 (X = Me); no rearrangement was observed with 50 (X = F), 58 (X = SiMe3), and 71 (X = CMe3).
A novel method for the conversion of the alcohol to the aldehyde via 1,5-silicon rearrangement
Moon,Kim
, p. 859 - 867 (2007/10/02)
A conceptually novel method for the conversion of alcohols to aldehydes is reported. The 1,5-silicon rearrangement is involved as the key element of the reaction.
Transition Metal Catalyzed Grignard Cross-Coupling to Ortho-Halogenated Aryl Imines. An Efficient Synthesis of Ortho-Substituted Aryl Aldehydes
Pridgen, N. Lendon,Snyder, L.,Prol, J.
, p. 1523 - 1526 (2007/10/02)
N-(o-Halogenated benzylidene)cyclohexylamines 2 were successfully reacted with reducing and nonreducing Grignard reagents in a transition metal catalyzed cross-coupling reaction resulting in an efficient single-step synthesis of ortho-substituted benzaldehydes after acidic workup.The dihalogenated benzylidene amines reacted regioselectively at the amine-activated ortho position to yield ortho-substituted halogenated benzaldehydes.
A New Approach to Asymmetric Synthesis of Polycycles on the Basis of o-Quinodimethane Generation
Ito, Yoshihiko,Amino, Yusuke,Nakatsuka, Masashi,Saegusa, Takeo
, p. 1586 - 1590 (2007/10/02)
The fluoride anion induced 1,4-elimination of 2-phenyl>-3,3-dimethyloxazolidinium salts generates (E,E)-α-alkyl-α'--o-quinodimethane intermediates, which are trapped stereoselectively with dienophiles to give polycycles.Intramolecular cyclization of 2-phenyl>-3,3-dimethyl-4-(R)-methyl-5(R)-phenyloxazolidinium triflate at 0 deg C produces a 3:1 diastereoisomeric mixture of 6--trans-octahydrophenanthrene, which is converted by hydrogenolysis on Pd/C to trans-octahydrophenanthrene with D +46.6 deg (50percent ee).Similarly, intramolecular cyclization of 2-phenyl>-3,3-dimethyl-4(S)-methoxymethyl-5(S)-phenyloxazolidinium triflate produces, after hydrogenolysis on Pd/C, trans-octahydrophenanthrene with D -51.1 deg (55percent ee).The enantioselection in the cycloaddition with o-quinodimethane intermediate may be accounted for on the basis of ?-stacking interaction in the Diels-Alder transition state.
