Highly diastereoselective formal nucleophilic substitution of bromocyclopropanes.
A highly diastereoselective formal nucleophilic substitution of bromocyclopropanes with oxygen- and nitrogen-based nucleophiles was demonstrated. The reaction proceeds via a base-assisted dehydrohalogenation producing a cyclopropene intermediate, which subsequently undergoes addition of a pronucleophile across the strained double bond. Very high chemoselectivity toward addition of primary and secondary alkoxides, as well as N-nucleophiles, in the presence of tert-butoxide base was observed, whereas phenoxides did not undergo addition under these reaction conditions. Facial selectivity of the addition can be efficiently controlled either by sterics or through a directing effect of an amide, carboxylate, and an o-aminomethylphenol function. Employment of tethered optically active amino alcohols as pronucleophiles allowed for efficient assembly of homochiral bicyclic compounds.
Alnasleh
Bassam K
BK
Department of Chemistry, The University of Kansas, 1251 Wescoe Hall Drive, Lawrence, Kansas 66045-75832, USA.
Sherrill
William M
WM
Rubina
Marina
M
Banning
Joseph
J
Rubin
Michael
M