Reactions of leyoglucosenone and its derivatives with diazo compounds*

摘要

The reaction of levoglucosenone with methyl diazoacetate gives first 1-pyrazoline, which then, depending on the reaction conditions, either undergoes denitrogenation to form a mixture of cyclopropane and unsaturated compounds, or isomerizes into 2-pyrazoline capable of easy cyclodimerizing in the presence of pyridine through the addition of the N-H fragments to the carbonyl groups. The product of levoglucosenone reduction, 6,8-dioxabicyclo[3.2.1]oct-2-en-4-ol, affords the corresponding cyclopropane upon the action of diazomethane in the presence of a Pd catalyst, whereas its reaction with methyl diazoacetate in the presence of Rh2(OAc)4 leads to the insertion of methoxycarbonyl carbene into the OH bond. From the ester obtained, 1-diazo-3-{6,8-dioxabicyclo[3.2.1]oct-2-en-4-yloxy}propan-2-one was synthesized in several steps, its denitrogenation under the action of copper compounds is accompanied by the intramolecular insertion of the carbene into the C(4)-H bond of the levoglucosenone fragment to yield the corresponding spirane.