1448775-66-3Relevant academic research and scientific papers
An Organocatalytic Cope Rearrangement
Kaldre, Dainis,Gleason, James L.
, p. 11557 - 11561 (2016)
The first example of an organocatalytic Cope rearrangement is reported. Acyclic and cyclic acyl hydrazides catalyze the rearrangement of 1,5-hexadiene-2-carboxaldehydes via iminium ion formation. A correlation between ring size and catalyst activity was observed for the cyclic hydrazides, with seven- and eight-membered-ring catalysts being the most active. Diazepane carboxylate 5 c (10 mol %) catalyzed the rearrangement of a range of dienes at room temperature in acetonitrile using triflic acid as a co-catalyst. Preliminary proof of principle for asymmetric catalysis was provided by rearrangement of 3,3-dimethyl-7-phenyl-1,5-heptadiene-2-carboxaldehyde in the presence of a novel 7-substituted diazepane carboxylate.
Diazepane Carboxylates as Organocatalysts in the Diels–Alder Reaction of α-Substituted Enals
H?ggman, Nicklas O.,Zank, Benjamin,Jun, HyunJune,Kaldre, Dainis,Gleason, James L.
, p. 5412 - 5416 (2018/10/20)
Ethyl diazepane carboxylate efficiently catalyzes the Diels–Alder cycloaddition of α-substituted-α,β-unsaturated aldehydes via iminium ion organocatalysis. The reaction is applicable to a range of dienes and dienophiles and generally proceeds at room temperature in the presence of 5 mol-% catalyst and 2.5 mol-% triflic acid co-catalyst. The incorporation of a stereogenic center on the diazepane backbone in combination with a menthyl carbamate produces a catalyst which affords enantioselectivities of 70–95 % ee for the cycloaddition of cyclopentadiene with a range of dienophiles. The enantioselectivity is rationalized via a transition state in which electrostatic stabilization by the carboxylate directs the diene to the more hindered face of the dienophile.
Enantioselective alkylation of aldehydes using functionalized alkylboron reagents catalyzed by a chiral titanium complex
Kumar, Ravindra,Kawasaki, Hiroki,Harada, Toshiro
supporting information, p. 4198 - 4201 (2013/09/12)
A practical method is developed for the synthesis of enantioenriched functionalized secondary alcohols through catalytic enantioselective alkylation of aldehydes. Functionalized alkylboron reagents, [FG-(CH2) n]3B (FG = Br, TIPSO, PhtN, CO2iPr, and CN) prepared from terminal olefin precursors by hydroboration, undergo enantioselective addition to aldehydes in the presence of a catalytic amount (5 mol %) of 3-(3,5-diphenylphenyl)-H8-BINOL and excess titanium tetraisopropoxide to afford the corresponding functionalized alcohols in high enantioselectivities up to 99% ee.
