Herein, we describe a new synthetic strategy towards an analogue
of the spiro-β-lactone-γ-lactam ring found in
a class of potent antibiotics, the oxazolomycins and lajollamycin.
The synthetic idea relies on the construction of two rings (β-lactone
and pyrrolidinone). The formation of the spiro-β-lactone
was accomplished by a crossed Cannizzaro reaction, while the 3,4-disubstituted
pyrrolidinone ring was constructed by a titanium(IV) chloride mediated chelation-controlled
double stereodifferentiating Crimmins aldol reaction of Garner’s
aldehyde.
Garner’s aldehyde - pyrrolidine - crossed
Cannizzaro reaction - Crimmins aldol reaction - lactones - Mitsunobu reaction
