124441-54-9Relevant articles and documents
Hammons,J.H. et al.
, p. 4493 - 4500 (1968)
Carbon Participation in the Solvolysis of Tertiary Norbornyl Derivatives. Norbornanes, Part 15. 6-Substituted 2-Methylnorbornyl 2-exo- and 2-endo-2,4-Dinitrophenyl Ethers
Grob, Cyril A.,Waldner, Adrian
, p. 2481 - 2488 (1983)
The solvolysis rates and products of the tertiary 2-methyl-2-exo- and -2-endo-norbornyl 2,4-dinitrophenyl ethers; 1 and 2, (X=2,4-(NO2)2C6H3O) have been determined.The different sensitivities of the rates of these ethers to the inductive effect of substituents at C(6) indicate that graded bridging of C(2) by C(6) occurs in the ionization of the exo-ethers 1, not, however, in the ionization of the endo ethers 2.In both cases hydrolysis leads to 2-methyl-2-exo-norbornanols only.Consequently, substitution takes place with retention at C(2) in the exo-series 1 and with inversion at C(2) in the endo-series 2.It is concluded that stereoelectronic and polar effects, rather than steric bulk effets, determine the high exo/endo rate ratios of the parent norbornyl derivatives 1a and 2a.
Rei,Brown
, p. 5335 (1966)
Photoinduced Fragmentation Borylation of Cyclic Alcohols and Hemiacetals
Aggarwal, Varinder K.,Madhavachary, Rudrakshula,Noble, Adam,Shu, Chao
supporting information, p. 7213 - 7218 (2020/10/12)
A visible-light photoinduced fragmentation borylation of O-phthalimido cycloalkanols with bis(catecholato)diboron is described. Structurally diverse keto and formyloxy alkyl boronic esters are shown to be conveniently prepared by radical-mediated ring opening of cyclic alcohols and hemiacetals, respectively. The reactions proceed under mild conditions in the absence of additives or photocatalysts, display excellent functional group tolerance, and are shown to allow cleavage of 4-, 5-, 6-, and 7-membered ring substrates. The mechanism proceeds via sequential homolytic N-O and C-C bond cleavages, the latter of which involves β-scission of an alkoxy radical, generating a carbonyl and an alkyl radical that is trapped by the diboron reagent. Spectroscopic studies suggest direct photoexcitation of either the phthalimide or diboron substrates with blue light can initiate a radical chain mechanism.
34. Norbornanes Part 20 Inductivity and Bridging in 2-Norbornyl Cations
Bielmann, Rolf,Fuso, Francesco,Grob, Cyril A.
, p. 312 - 319 (2007/10/02)
The solvolysis rates and products of several 1-substituted 2-exo- and 2-endo-norbornyl p-toluenesulfonates 7 and 8, respectively, have been determined.Hydrolyses of these epimeric tosylates yielded rearranged products in varying amounts, except when the substituent was COOCH3 or CN.The logarithms of the rate constants (log k) for the endo-series 8 correlated linearly with the corresponding inductive constants ?q1 with a reaction constant ρ1 of -1.24.On the other hand, log k values for the exo-series 7 appear to fit two regression lines,the first line (ρ1 = -1.90) defined by the tosylates that ionize, with rearrangement, to the tertiary cations 11, the second (ρ1 = -1.86) by the tosylates 7(R = H, COOCH3, and CN) that ionize to an asymetrically bridged secondary cation 19.These results confirm the unique participation of C(6) with a ρ1 of -2.00 in the ionization of 2-exo-norbornyl tosylate.
