Structure-enantioselectivity effects in 3,4-dihydropyrimido[2,1-b]benzothiazole-based isothioureas as enantioselective acylation catalystsElectronic supplementary information (ESI) available: Experimental procedures, HPLC data and spectroscopic data for all new products is available. See DOI: 10.1039/c0ob00515k

• Main Authors: Belmessieri, Dorine, Joannesse, Caroline, Woods, Philip A, MacGregor, Callum, Jones, Caroline, Campbell, Craig D, Johnston, Craig P, Duguet, Nicolas, Concellón, Carmen, Bragg, Ryan A, Smith, Andrew D
• Format: Article
• Language: English
• ISSN: 1477-0520; 1477-0539
• DOI: 10.1039/c0ob00515k

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, (2 S ,3 R )-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. Screening of a range of 3,4-dihydropyrimido[2,1-b]benzothiazole-based acylation catalysts reveals that (2 S ,3 R )-2-phenyl-3-isopropyl substitution proved optimal. Low catalyst loadings (0.10-0.25 mol%) of this optimal isothiourea can be used to generate enantiopure alcohols (>99% ee) in good yields.