Scheme 1.

General Synthetic Route to PVHIs^a

^a Conditions and reagents (General Procedures are detailed in Experimental Section): GP1, N,O-dimethylhydroxylamine hydrochloride, T3P, DIPEA, DCM, and 0 °C; GP2, LAH, THF, and −10 °C; GP3, (1) NaBH₄, EtOH, and 0 °C and (2) SOCl₂ and DCM; GP4, PPh₃, benzene, and reflux; GP5, P(OEt)₃ and 150 °C; GP6, LHMDS, THF, −70 to 0 °C; GP7, LHMDS, THF, −70 to 0 °C; GP8, (1) TFA, DCM, and 0 °C and (2) R₁-Xaa-OH, T3P, DIPEA, DCM, and 0 °C; GP9, MeI, MeCN, and reflux; GP10, (1) LiOH and H₂O and (2)ClCOOEt and NH₄Cl.