951008-57-4Relevant academic research and scientific papers
Intramolecular [2+2] Photocycloaddition of Cyclic Enones: Selectivity Control by Lewis Acids and Mechanistic Implications
Poplata, Saner,Bauer, Andreas,Storch, Golo,Bach, Thorsten
supporting information, p. 8135 - 8148 (2019/05/29)
The intramolecular [2+2] photocycloaddition of 3-alkenyl-2-cycloalkenones was performed in an enantioselective fashion (nine representative examples, 54–86 % yield, 76–96 % ee) upon irradiation at λ=366 nm in the presence of an AlBr3-activated oxazaborolidine as the Lewis acid. An extensive screening of proline-derived oxazaborolidines showed that the enantioface differentiation depends strongly on the nature of the aryl group at the 3-position of the heterocycle. DFT calculations of the Lewis acid–substrate complex indicate that attractive dispersion forces may be responsible for a change of the binding mode. The catalytic [2+2] photocycloaddition was shown to proceed on the triplet hypersurface with a quantum yield of 0.05. The positive effect of Lewis acids on the outcome of a given intramolecular [2+2] photocycloaddition was illustrated by optimizing the key step in a concise total synthesis of the sesquiterpene (±)-italicene.
Nonenzymatic acylative kinetic resolution of Baylis-Hillman adducts
O Dalaigh, Ciaran,Connon, Stephen J.
, p. 7066 - 7069 (2008/02/11)
(Chemical Equation Presented) The first efficient nonenzymatic acylative kinetic resolution of Baylis-Hillman adducts is reported. Chiral pyridine catalyst 1a and an optimized analogue 1e are capable of promoting the synthetically useful enantioselective
