A series of functionalized 2,3-dihydro-1,4-benzoxazines were obtained in moderate to excellent yields via domino [5 + 1] annulations of 2-halo-1,3-dicarbonyl compounds 2 with imines 1 under mild conditions and the application of this method in the synthesis of bioactive analogues, such as functionalized tetracyclic-1,4-benzoxazines which contain two new heterocyclic rings and one quaternary carbon
Neighboring phenolic group-activated <i>gem</i>-difluoroallylboration of imines for the catalyst-free synthesis of <i>gem</i>-difluorohomoallylamines
作者:Xing Yang、Feng Zhang、Yang Zhou、Yi-Yong Huang
DOI:10.1039/c8ob00541a
日期:——
We herein report an unprecedented addition reaction of pinacol gem-difluoroallylborates and imines enabled by a neighboring phenolic group in an N-protecting group under catalyst-free conditions, thus facilitating the construction of a wide range of racemic gem-difluorohomoallylamine derivatives. Based on the control experiments, a plausible transition state via the Zimmerman–Traxler model was proposed
A direct highly diastereo- and enantioselective asymmetricvinylogousMannich-type (AVM) reaction of aldimines with nonactivated natural α-angelica lactone has been successfully developed. It was demonstrated that the nonactivated natural α-angelica lactone is a useful vinylogous nucleophile to give the chiral δ-amino γ,γ-disubstituted butenolide carbonyl derivatives. The N,N′-dioxide L2–ScIII complex