The IminoboranetBuB?NtBu as a Dipolarphile in (2+3) Cycloadditions
摘要:
AbstractThe iminoborane tBuB≡NtBu and the diazomethane tBuCH=N2 give the (2+3) cycloadduct [—HC(tBu)—N=N—N(tBu)=B(tBu)—] in a 1:1 reaction and the seven‐membered ring [—C(tBu)=N—NH—N(tBu)=B(tBu)—N(tBu)=B(tBu)—] in a 2:1 reaction. The (2+3) cycloadduct decomposes above 0 °C to give the seven‐membered ring, N2, and HC(tBu)=N—N=CH(tBu) in the ratio 2:1:1. The borane tBuB≡NtBu and organic azides R″N3 yield the (2+3) cycloadducts [—R″N—N=N—N(tBu)=B(tBu)—] (R″ = Me, Et, Pr, Bu, iBu, sBu, C5H11, c‐C5H9, c‐C6H11, Bzl, EtOOC).