Zirconocene-catalyzed kinetic resolution of dihydrofurans
摘要:
Zisconocene-catalyzed kinetic resolution of dihydrofurans may be effected in the presence of 10 mol% non-racemic (EBTHI)ZrCl2. Transformations reported herein proceed efficiently to afford two constitutionally distinct and readily separable products with excellent levels of diastereo- and enantioselectivity. Preparation and resolution of the substrate furans may be carried out in a single pot.
Triphenylphosphine-Induced Ring Contraction of 1,2-Dioxines
摘要:
Triphenylphosphine inserts into the peroxide bond of 1,2-dioxines, initiating ring contraction with loss of triphenylphosphine oxide. This process yields dihydrofuran oxides in 54-97% yield from oxirenyl[2,3-c] [1,2]dioxines and dihydrofurans from 3,6-dihydro-1,2-dioxines with inversion of stereochemistry at either the 2 or 5 position in the furan product.