reported. The approach is based on a silvernitrate‐catalyzed cyclo‐isomerization reaction of oxygenated propargylic sulfinamides and provides efficiently 5‐membered endocyclic sulfoximines (isothiazole 1‐oxide). These new heterocyclic scaffolds can be isolated or directly converted into cyclic sulfinamides via Lewis acid‐mediated sulfur dealkylation reactions.
The addition of dimethylaluminium alkoxyacetylides to Ellman's sulfinylimines is described. The reaction proceeds with excellent diastereoselectivity and high yield to produce oxygenated propargylamines in one step starting from simple dichloroenol ethers.
Lewis Acid Catalyzed Intramolecular Condensation of Ynol Ether-Acetals. Synthesis of Alkoxycycloalkene Carboxylates
作者:Vincent Tran、Thomas G. Minehan
DOI:10.1021/ol303026v
日期:2012.12.7
Treatment of ynol ether-tethered dialkyl acetals with catalytic quantities of scandium triflate in CH3CN gives rise to five-, six-, and seven-membered alkoxycycloalkene carboxylates in good to excellent yields. Tri- and tetrasubstituted carbocyclic and heterocyclic alkenes may be formed by this method, and the products obtained may serve as useful intermediates for natural product synthesis.
Asymmetric Addition of Alkoxy Ethynyl Anion to Chiral <i>N</i>-Sulfinyl Imines
The addition of lithiated ynol ethers to chiral N-sulfinyl imines proceeds in high yield and diastereoselectivity. The selectivity is completely reversed by the addition of boron trifluoride. These alkoxypropargyl sulfinamides can be reduced to afford enol ethers, selectively oxidized to busyl derivatives, or the ynol ether can be hydrolyzed to afford beta-amino esters.