Thermal and photochemical decomposition of N- [2-( 3,3-Dimethyl-1-butynyl)-2,5,5-trimethyl-1-pyrrolidinyl] nitrene

Article abstract of DOI:10.1021/ja00041a021

Oxidation of N-aminopyrrolidine 5 with tert-butyl hypochlorite at -130 °C yields the 1,1-disubstituted diazene 4, which is stable in dimethyl ether solution at this temperature. Thermal (-90 °C) or photochemical (-130 deg;C, λ > 330 nm) decomposition of 4 furnishes singlet alkyl propargyl biradical 1, which undergoes fragmentation to 16, cyclization to 17, and disproportionate to 18 and 19 (Table I). The absence of products attributable to the cyclization of 1 to vinyl carbene 2 (cf. eq 1) is interpreted as evidence that cyclization according to eq 1, when observed, occurs directly from the triplet biradical in competition with intersystem crossing.