139420-77-2Relevant academic research and scientific papers
Diastereomerically Pure 3-(Silyloxy)oxetanes by a Selective Paterno-Buechi Reaction
Bach, Thorsten,Joedicke, Kai
, p. 2457 - 2466 (2007/10/02)
Diastereomerically pure 3-oxetanes 3 were prepared in moderate to good yields (45-72percent) by the Paterno-Buechi reaction of silyl enol ethers 2 with benzaldehyde.The phorocycloaddition exhibits a high degree of regio- and diastereoselectivity.The substituents R in the silyl enol ether have been varied , and it was found that steric bulk is mainly responsible for enhanced selectivity (diastereoselectivity from 70:30 up to 95:5).The regiochemical control is perfect (regioselectivity > 95:5) except for silyl enol ether 2a (R = Me) in the case of which a 90:10 ratio of regioisomers was observed.Irradiation of the reaction mixture at lower temperature (-25 deg C) led to a further improvement of diastereoselectivity.The relative configuration of the products obtained was elucidated both by 1H-NMR spectroscopy and by chemical degradation.As a mechanistic hypothesis to explain the high observed diastereoselectivity we propose that the steric environment in the intermediate diradical 11 determines the stereoselectivity according to two possible reaction pathways, i.e. bond formation and retrocleavage. - Key Words: Paterno-Buechi reaction / Oxetanes / Diastereoselectivity / Enol silyl ethers / Photocycloaddition
3-Trimethylsilyloxy-oxetanes via a highly selective Paterno-Buchi reaction
Bach
, p. 7037 - 7038 (2007/10/02)
Benzaldehyde reacts photochemically with various trimethylsilyl enol ethers to furnish 3-trimethylsilyloxy-oxetanes in moderate to fair fields. The photocycloaddition proceeds with excellent regio- and diastereoselectivity.
