title: Position of coordination of the lithium ion determines the regioselectivity of demethylations of 3,4-dimethoxymorphinans with L-selectride.
abstract: [reaction: see text] L-Selectride is an efficient agent for the 3-O-demethylation of opioids and is known to cleave the least hindered methoxyl group in a molecule. The treatment of a 3,4-dimethoxymorphinan containing a 6-ketal with L-Selectride gave selective 4-O-demethylation, rather than cleavage of the less hindered 3-methoxyl. In contrast, a 3,4-dimethoxymorphinan lacking a 6-ketal gave selective 3-O-demethylation, suggesting that the regiochemistry of L-Selectride-mediated O-demethylation can be manipulated through altering the position of coordination of the lithium ion.
authors.affiliation: Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, Maryland 21201, USA.
authors.forename: Huifang
authors.initials: H
authors.lastname: Wu
authors.forename: Linn N
authors.initials: LN
authors.lastname: Thatcher
authors.forename: Denzil
authors.initials: D
authors.lastname: Bernard
authors.forename: Damon A
authors.initials: DA
authors.lastname: Parrish
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Deschamps
authors.forename: Kenner C
authors.initials: KC
authors.lastname: Rice
authors.forename: Alexander D
authors.initials: AD
authors.lastname: MacKerell
authors.forename: Andrew
authors.initials: A
authors.lastname: Coop
mesh_terms: D002384:Catalysis; D007202:Indicators and Reagents; D008094:Lithium / Q000737:chemistry*; D015394:Molecular Structure; D009019:Morphinans / Q000737:chemistry*; D009294:Narcotics / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D007202:Indicators and Reagents; D009019:Morphinans; D009294:Narcotics; D008094:Lithium