Are there alternatives to Tert-butyl 1-oxa-7-azaspiro[3.5]nonane-7-carboxylate (CAS: 864684-96-8) in synthesis?

Alternatives to Tert-butyl 1-oxa-7-azaspiro[3.5]nonane-7-carboxylate (CAS: 864684-96-8) in synthesis include other aza-spiro compounds with similar functional groups, such as tert-butyl 1-oxa-7-azaspiro[4.5]decane-7-carboxylate. Common alternative reagents include substituted carboxylic acids and aza-spiro compounds. Isomers and analogs can also serve as viable alternatives, depending on the specific requirements of the synthesis.