Fig. 5: Synthesis of alkylidene carbene precursors 22 and 29. | Nature Communications

Fig. 5: Synthesis of alkylidene carbene precursors 22 and 29.

From: Probing the alkylidene carbene–strained alkyne equilibrium in polycyclic systems via the Fritsch–Buttenberg–Wiechell rearrangement

Fig. 5

Yields reported represent isolated yields. Reagents and conditions: i) TBPB, CuBr, benzene, reflux, ii) Pd(OAc)2/C, H2, MeOH, iii) TMS-I, CHCl3, NaHCO3, MeOH, iv) PCC, CH2Cl2, v) 23, Cp2TiCl2, Mg, P(OEt)3, 4 Å mol. sieves, THF, RT vi) ethylene glycol, pTsOH, benzene vii) LiAlH4, Et2O, reflux, HCl, H2O, viii) NH2NH2 • H2O, diethylene glycol, Δ, KOH, reflux, ix) CrO3, H2O, AcOH, Δ. aMixture of exo and endo diastereomers.

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