Quantitation in the regioselectivity of acylation of glycosyl diglycerides: total synthesis of a Streptococcus pneumoniae α-glucosyl diglyceride

The fidelity of acylation regioselectivity in the synthesis of mixed glycosyl diacylglycerols can be accurately measured by quantitative 13C NMR spectroscopy using a 1-13C-labelled fatty acid and a paramagnetic relaxation enhancement agent. Exquisite regioselectivity is achieved using a stepwise acylation/substitution of a glycosyl β-bromohydrin, which is applied to the total synthesis of Streptococcus pneumoniae Glc-DAG-s2.