Palladium-catalyzed synthesis of tetrahydrofurans from gamma-hydroxy terminal alkenes: scope, limitations, and stereoselectivity.
A new, stereoselective synthesis of substituted tetrahydrofurans via Pd-catalyzed reactions of aryl and vinyl bromides with gamma-hydroxy terminal alkenes is described. This transformation affords trans-2,5- and trans-2,3-disubstituted tetrahydrofurans with up to >20:1 dr. This methodology also provides access to bicyclic and spirocyclic tetrahydrofuran derivatives in good yield with 10-20:1 dr. The scope and limitations of these transformations are discussed in detail, as are the effect of substrate sterics and electronics on yield and stereoselectivity. A proposed mechanism of these transformations is presented along with a model that rationalizes the stereochemical outcome of the reactions.
Hay
Michael B
MB
Department of Chemistry, University of Michigan, 930 North University Avenue, Ann Arbor, MI 48109-1055, USA.
Hardin
Alison R
AR
Wolfe
John P
JP