[CH3:1][O:2][C:3]([C@@H:5]1[CH2:7][C@H:6]1[C:8](O)=[O:9])=[O:4].B(OC)(OC)OC.[Cl-].[Na+]>O1CCCC1>[CH3:1][O:2][C:3]([C@@H:5]1[CH2:7][C@H:6]1[CH2:8][OH:9])=[O:4]Add boranemethyl sulfide complex (177 mL, 0.354 mol), slowly, by means of a dropping funnel, to a stirring solution of trans-cyclopropane-1,2-dicarboxylic acid monomethyl ester (Example 3a) (25.5 g, 0.177 mol), trimethyl borate (60.3 mL, 0.531 mol) and tetrahydrofuran (150 mL) at 0° C. After complete addition, allow the reaction to come to ambient temperature and stir for 2 h more. Pour the reaction mixture into a stirring solution of 50% aqueous sodium chloride solution (1.5 L)-concentrated HCl (10 mL). Extract the mixture with ethyl acetate (EtOAc) (3 times), combine the extracts, dry (Na2SO4) and concentrate the solvent to obtain a colorless oil: 22.6 g.
Wird geladen…
