Zn-Catalyzed Enantio- and Diastereoselective Formal [4 + 2] Cycloaddition Involving Two Electron-Deficient Partners: Asymmetric Synthesis of Piperidines from 1-Azadienes and Nitro-Alkenes
We report a catalytic asymmetric synthesis of piperidines through [4 + 2] cycloaddition of 1-azadienes and nitro-alkenes. The reaction uses earth abundant Zn as catalyst and is highly diastereo- and regioselective. A novel BOPA ligand (F-BOPA) confers high reactivity and enantioselectivity in the process. The presence of ortho substitution on the arenes adjacent to the bis(oxazolines) was found to be particularly impactful, due to limiting the undesired coordination of 1-azadiene to the Lewis acid and thus allowing the reaction to be carried out at lower temperature. A series of secondary kinetic isotope effect studies using a range of ligands implicates a stepwise mechanism for the transformation, involving an initial Michael-type addition of the imine to the nitro-alkene followed by a cyclization event. The stepwise mechanism obviates the electronic requirement inherent to a concerted mechanism, explaining the successful cycloaddition between two electron-deficient partners. (Chemical Equation Presented).
Chu, John C. K.,Dalton, Derek M.,Rovis, Tomislav
supporting information
p. 4445 - 4452
(2015/04/14)
THE SYNTHESIS OF 9-OXO-9,10-DIHYDROACRIDINE-4-CARBOXYLIC ACIDS VIA THE JOURDAN-ULLMANN REACTION OF ANTHRANILIC ACIDS AND METHYL 2-IODOBENZOATES
Reaction between anthranilic acids and methyl 2-iodobenzoates under anhydrous Jourdan-Ullmann conditions gives good to excellent yields of 2-(2-methoxycarbonylphenyl)anthranilic acids, required precursors for the unequivocal synthesis of substituted 9-oxo
Rewcastle, Gordon W.,Denny, William A
p. 309 - 318
(2007/10/02)
The Synthesis of Substituted 9-Oxoacridan-4-carboxylic Acids; Part 3. The Reaction of Methyl Anthranilates with Diphenyliodonium-2-carboxylates
-
Rewcastle, Gordon W.,Denny, William A.
p. 220 - 222
(2007/10/02)
More Articles about upstream products of 100038-81-1