Hypervalent Iodine Reagent Mediated Oxidative Heterocyclization of Aldoximes with Heterocyclic Alkenes
作者:Akira Yoshimura、Khiem C. Nguyen、Gregory T. Rohde、Pavel S. Postnikov、Mekhman S. Yusubov、Viktor V. Zhdankin
DOI:10.1021/acs.joc.7b01462
日期:2017.11.17
An efficient cycloaddition of heterocyclic alkenes with nitrile oxides generated in situ from the corresponding aldoximes using organohypervalent iodine(III) reagent, [hydroxy(tosyloxy)iodo]benzene (Koser’s reagent), has been developed. The oxidative cyclization of various aldoximes with 1-propene-1,3-sultone affords the respective isoxazoline-ring-fused heterobicyclic products in moderate to good
Unsaturated sultones with normal, medium and large ring sizes were efficiently synthesized by ring closing metathesis of sulfonates. The required substrates were readily derived from alkenols and olefinic sulfonyl chlorides.
synthesized by ring closing metathesis (RCM) of sulfonates. The resulting α,β-unsaturated sultones act as dienophiles in intermolecular Diels-Alder reactions. A first cyclic sulfate formation throughRCM has been discovered, and a rapid access to p-lactams fused to a sultam moiety of variable ring size was developed from inexpensive, commercially available starting materials using RCM as the key operation
A number of bicyclicchiralsultams were synthesized based on 1,3-dipolar cycloaddition reactions of nitrile oxides and nitrones with prop-1-ene-1,3-sultone. The corresponding N-enoyl sultams were prepared by acylation. Their relative effectiveness as new chiral auxiliaries in asymmetric synthesis was evaluated for the asymmetric Diels–Alder reactions with cyclopentadiene. Good chemical yield and excellent
1,3-Dipolar cycloadditions of prop-1-ene-1,3-sultone with nitrile oxides/nitrones
作者:H. Zhang、W.H. Chan、Albert W.M. Lee、W.Y. Wong
DOI:10.1016/s0040-4039(02)02502-9
日期:2003.1
scope and limitations of dipolar cycloaddition reactions between nitrile oxides/nitrones and prop-1-ene-1,3-sultone have been investigated. A remarkably high degree of regioselectivity and stereoselectivity was observed. The homochiral sultam 8e was synthesized in a four-step reaction sequence starting from the substituted isoxazoline 4e obtained from the cycloaddition. The absolute stereochemistry of