Ring-closing metathesis in an enantioselective synthesis of the macrocyclic core of crassin acetate
作者:Gunnar Herstad、Peter P. Molesworth、Charlotte M. Miller、Tore Benneche、Marcus A. Tius
DOI:10.1016/j.tet.2016.02.050
日期:2016.4
The formation of the macrocyclic core of crassin acetate from an acyclic precursor could be effected by ring-closing alkyne metathesis reactions while ring-closing olefin metathesis reactions failed. Installment of necessary stereochemistry was achieved by Sharpless asymmetric epoxidations on allylicalcohols obtained from geranyl acetate or farnesyl acetate. The macrocyclic core of crassin acetate
Lewis Acid Promoted Phenylseleno Group Transfer Tandem Radical Cyclization Reactions
作者:Dan Yang、Qiang Gao、On-Yi Lee
DOI:10.1021/ol025750n
日期:2002.4.1
[reaction: see text] A new Lewis acid promoted phenylseleno group transfer tandem radical cyclization method was developed. In the presence of Lewis acids such as Yb(OTf)3 or Mg(ClO4)2, under photolysis condition at low temperature (-45 degrees C), various unsaturated alpha-phenylseleno beta-keto amides underwent radical cyclization reactions to give monocyclic or bicyclic products in a highly efficient