“…A major path of this acetolysis proceeds without accompanying rearrangement. Interest in the changes of the rearrangement manner with unsaturation led us to undertake a study of the dibenzonorbornadienyl-1 -carbinyl system (5) and, in addition, the Scheme I (6). With these present results the solvolytic behavior of bicyclo[2.2.1] bridgehead neopentyl systems will be complete.…”
mentioning
confidence: 79%
“…Solvolysis of bicyelic bridgehead neopentyl systems proceeds with ready rearrangements forming bridgehead substituted products.1 A representative example is the acetolysis of norbornyl-l-carbinyl tosylate (1-OTs) which produced bicyclo[2.2.2]octyl-l-yl acetate in 85% yield.2 Effects of unsaturation in the [2.2.1] system have been investigated by Wilt, Bly, and their co-workers with norbornenyl-1 -carbinyl tosylate (2)3•4 and benzonorbornenyl-1-carbinyl tosylate (3). 5 Of particular interest are the absence of etheno (or benzo) bridge-migrated products and the formation of considerable amounts of unrearranged products. Introduction of additional unsaturation has been investigated by Chenire et al 6 with benzonorbornadienyl-l-carbinyl tosylate (4).…”
The preparation of dibenzonorbornadienyl-1-carbinyl derivatives (5) is described. The acetolysis of the trifluoromethanesulfonic acid ester (triflate, gives the acetate with retention of configuration and the internally returned dit~enzobicyclo[2.2.2]octadien-l-y1 triflate (13). The acetolysis of the benzonorbornadienyl-1-carbinyl system (4) previously reported is reinvestigated using the triflate and shown to proceed by a similar pathway. The acetolysis of dibenzobicyclo[2.2.2]octadienyl-l-carbinyl triflate (6-OTf) gives only the ring-enlarged dibenzobicyclo[3.2.2]nonadien-l-y1 acetate (14). These rates and products are compared with those reported in acetolyses of norbornyl-1-carbinyl (I), norbornenyl-1-carbinyl (2), and benzonorbornenyl-1-carbinyl (3) arenesulfonates. The absence of the unsaturated bridge-migrated products is established. The dissociation constants of the corresponding bridgehead acids are determined in 50% aqueous ethanol. A linear relation is found between the logarithms of the acetolysis rates and the dissociation constants. Therefore, evidence for anchimeric assistance by the unsaturated link,sge in these systems is not found; rather the inductive effect of these bonds accounts for the results observed.Solvolysis of bicyclic bridgehead neopentyl systems proceeds with ready rearrangements forming bridgehead substituted pr0ducts.l A representative example is the acetolysis of norbornyl-1-carbinyl tosylate (1-OTs) which produced
bicyclo[2.2.2]octyl-l-yl acetate in 85% yield.2 Effects of unsaturation in the [2.2.1] system have been investigated by Wilt,Bly, and their co-workers with norbornenyl-1-carbinyl tosylate (2)374 and benzonorbornenyl-1-carbinyl tosylate (3).5 Of particular interest are the absence of etheno (or benzo) bridge-migrated products and the formation of considerable amounts of unrearranged products. Introduction of additional unsaturation has been investigated by Chenire e t a1.6 with benzonorbornadienJy1-1-carbinyl tosylate (4). A major path of this acetolysis proceeds without accompanying rearrangement. Interest in the changes of the rearrangement manner with unsaturation led us t o undertake a study of the dibenzonorbornadienyl-1-carbinyl system (5) and, in addition, the Scheme I CH2X A --C H~O T S I -OTS A3 OAc CH2X CH2X 2 3 CH2X 4 5 6 butadiene COOR 7 R = E t a R = H COOR COOMe 9 R = H 10 R = Me @& + @& -5-OTf (OTf-OS02CFd COOMe C H20H 12 5 -O H dibenzobicyclo[2.2.2]octadienyl-l-carbinyl system (6). With these present results the solvolytic behavior of bicyclo[2.2.1] bridgehead neopentyl systems will be complete.
“…A major path of this acetolysis proceeds without accompanying rearrangement. Interest in the changes of the rearrangement manner with unsaturation led us to undertake a study of the dibenzonorbornadienyl-1 -carbinyl system (5) and, in addition, the Scheme I (6). With these present results the solvolytic behavior of bicyclo[2.2.1] bridgehead neopentyl systems will be complete.…”
mentioning
confidence: 79%
“…Solvolysis of bicyelic bridgehead neopentyl systems proceeds with ready rearrangements forming bridgehead substituted products.1 A representative example is the acetolysis of norbornyl-l-carbinyl tosylate (1-OTs) which produced bicyclo[2.2.2]octyl-l-yl acetate in 85% yield.2 Effects of unsaturation in the [2.2.1] system have been investigated by Wilt, Bly, and their co-workers with norbornenyl-1 -carbinyl tosylate (2)3•4 and benzonorbornenyl-1-carbinyl tosylate (3). 5 Of particular interest are the absence of etheno (or benzo) bridge-migrated products and the formation of considerable amounts of unrearranged products. Introduction of additional unsaturation has been investigated by Chenire et al 6 with benzonorbornadienyl-l-carbinyl tosylate (4).…”
The preparation of dibenzonorbornadienyl-1-carbinyl derivatives (5) is described. The acetolysis of the trifluoromethanesulfonic acid ester (triflate, gives the acetate with retention of configuration and the internally returned dit~enzobicyclo[2.2.2]octadien-l-y1 triflate (13). The acetolysis of the benzonorbornadienyl-1-carbinyl system (4) previously reported is reinvestigated using the triflate and shown to proceed by a similar pathway. The acetolysis of dibenzobicyclo[2.2.2]octadienyl-l-carbinyl triflate (6-OTf) gives only the ring-enlarged dibenzobicyclo[3.2.2]nonadien-l-y1 acetate (14). These rates and products are compared with those reported in acetolyses of norbornyl-1-carbinyl (I), norbornenyl-1-carbinyl (2), and benzonorbornenyl-1-carbinyl (3) arenesulfonates. The absence of the unsaturated bridge-migrated products is established. The dissociation constants of the corresponding bridgehead acids are determined in 50% aqueous ethanol. A linear relation is found between the logarithms of the acetolysis rates and the dissociation constants. Therefore, evidence for anchimeric assistance by the unsaturated link,sge in these systems is not found; rather the inductive effect of these bonds accounts for the results observed.Solvolysis of bicyclic bridgehead neopentyl systems proceeds with ready rearrangements forming bridgehead substituted pr0ducts.l A representative example is the acetolysis of norbornyl-1-carbinyl tosylate (1-OTs) which produced
bicyclo[2.2.2]octyl-l-yl acetate in 85% yield.2 Effects of unsaturation in the [2.2.1] system have been investigated by Wilt,Bly, and their co-workers with norbornenyl-1-carbinyl tosylate (2)374 and benzonorbornenyl-1-carbinyl tosylate (3).5 Of particular interest are the absence of etheno (or benzo) bridge-migrated products and the formation of considerable amounts of unrearranged products. Introduction of additional unsaturation has been investigated by Chenire e t a1.6 with benzonorbornadienJy1-1-carbinyl tosylate (4). A major path of this acetolysis proceeds without accompanying rearrangement. Interest in the changes of the rearrangement manner with unsaturation led us t o undertake a study of the dibenzonorbornadienyl-1-carbinyl system (5) and, in addition, the Scheme I CH2X A --C H~O T S I -OTS A3 OAc CH2X CH2X 2 3 CH2X 4 5 6 butadiene COOR 7 R = E t a R = H COOR COOMe 9 R = H 10 R = Me @& + @& -5-OTf (OTf-OS02CFd COOMe C H20H 12 5 -O H dibenzobicyclo[2.2.2]octadienyl-l-carbinyl system (6). With these present results the solvolytic behavior of bicyclo[2.2.1] bridgehead neopentyl systems will be complete.
“…A multistep preparation of fluorobenzoquinone (2) has been reported,9 but its characterization was limited to elemental analysis. We now report simple preparations from commercially available starting materials of 1, 2, and trifluoromethylhydroquinone (3) ,10 and polarographic half-wave potentials for oxidation of 1 and 3.…”
“…7.0-7.4 (m, 4, ArH), 4.66 (AB, 2, CH20, J = 20 Hz), 4.4-4.8 (m, 1, CHO), 3.3-3.5 (m, 1, CH), 2.07 (s) 3, CH3), 2.05 (s, 3, CH3), 1.7-2.2 (m, 4, two CII2C). Two peaks in a ratio of 84:16 were observed by glc.…”
Section: Table I Acetolysis Studiesmentioning
confidence: 99%
“…Solvolysis of 3e also gives a similar tosylate (6) isolated in 14% yield. 4 In our study all attempts to identify any tosylate (such as 7) in the crude product mixture Tosylate Neopentyl Neopentyl Neophyl Norbornyl-1carbinyl (le)…”
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