Supplier Page from Thermo Fisher Scientific for Tungsten(VI) ethoxide, 99.8% (metals basis), 5% w/v in ethanol
4-Bromobutyric acid, 98% from Thermo Fisher Scientific
Methyl 5-bromovalerate, 97% from Thermo Fisher Scientific
Methyl acetoacetate, 99+% from Thermo Fisher Scientific
Methyl chloroformate, 99% from Thermo Fisher Scientific