Capture–Collapse Heterocyclization: 1,3-Diazepanes by C–N Reductive Elimination from Rhodacyclo­pentanones

Rhodacyclopentanones derived from carbonylative C–C activation of cyclopropyl ureas can be “captured” by pendant nucleophiles prior to “collapse” to 1,3-diazepanes. The choice of N-substituent on the cyclopropane unit controls the oxidation level of the product, such that C4–C5 unsaturated or saturated systems can be accessed selectively.由环丙基脲经羰基化C-C键活化制备的铑杂环戊酮（Rhodacyclopentanones），可在发生“裂解”生成1,3-二氮杂环庚烷（1,3-diazepanes）前，被侧链亲核试剂“捕获”。环丙烷单元上的N取代基选择可调控产物的氧化态，从而能够选择性地得到C4-C5不饱和或饱和体系。