title: Structure-enantioselectivity effects in 3,4-dihydropyrimido[2,1-b]benzothiazole-based isothioureas as enantioselective acylation catalysts.
abstract: The catalytic activity and enantioselectivity in the kinetic resolution of (±)-1-naphthylethanol with a range of structurally related 3,4-dihydropyrimido[2,1-b]benzothiazole-based catalysts is examined. Of the isothiourea catalysts screened, (2S,3R)-2-phenyl-3-isopropyl substitution proved optimal, giving good levels of selectivity in the kinetic resolution of a number of secondary alcohols (S values up to >100 at ~50% conversion). Low catalyst loadings (0.10-0.25 mol%) of the optimal isothiourea can be used to generate enantiopure alcohols (>99% ee) in good yields.
authors.affiliation: EastCHEM, School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife, UK.
authors.forename: Dorine
authors.initials: D
authors.lastname: Belmessieri
authors.forename: Caroline
authors.initials: C
authors.lastname: Joannesse
authors.forename: Philip A
authors.initials: PA
authors.lastname: Woods
authors.forename: Callum
authors.initials: C
authors.lastname: MacGregor
authors.forename: Caroline
authors.initials: C
authors.lastname: Jones
authors.forename: Craig D
authors.initials: CD
authors.lastname: Campbell
authors.forename: Craig P
authors.initials: CP
authors.lastname: Johnston
authors.forename: Nicolas
authors.initials: N
authors.lastname: Duguet
authors.forename: Carmen
authors.initials: C
authors.lastname: Concellón
authors.forename: Ryan A
authors.initials: RA
authors.lastname: Bragg
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Smith
mesh_terms: D000215:Acylation; D000588:Amines / Q000737:chemistry; D052160:Benzothiazoles / Q000737:chemistry*; D002384:Catalysis; D015394:Molecular Structure; D013237:Stereoisomerism; D013890:Thiourea / Q000737:chemistry*
chemical_list: D000588:Amines; D052160:Benzothiazoles; C005465:benzothiazole; D013890:Thiourea