A new chiral auxiliary for asymmetric thermal reactions: high stereocontrol in radical addition, allylation, and annulation reactions

A new imide chiral auxiliary, endo-7-(2-benzoxazolyl)-1,5,7-trimethyl-3-azabicyclo[3.3.1]nonan-2-one (5), is from Kemp's triacid and resolved via its menthyl carbamate. Mixed fumarate derivatives of the auxiliary show unprecedented control of regiochemistry and β-stereochemistry in representative radical addition reactions. Chiral radicals derived from 5 also show extremely high levels of stereoselectivity in representative radical allylation and cyclization reactions. Structural features of the chiral auxiliary and features of radical addition are integrated into a model for stereoselection