WCl6, 1, reacted with two equivalents of HC(O)NR2 (R = Me, Et) in CH2Cl2 to afford the W(vi) oxo-derivatives WOCl4(OCHNR2) (R = Me, 2a; R = Et, 2b) as main products. The hexachlorotungstate(v) salts [{OC-N(Me)CH2CH2CH 2}2(μ-H)][WCl6], 3, and [PhNHC(Me)N(Ph)C(O) Me][WCl6], 4, were isolated in moderate yields from the 1:2 molar reactions of 1 with N-methyl-2-pyrrolidone (in CH2Cl2) and acetanilide (in CDCl3), respectively. The additions of two equivalents of ketones/aldehydes to 1/CH2Cl2 yielded the complexes WOCl4[OC(R)(R′)] (R = Me, R′ = Ph, 5a; R = R′ = Ph, 5b; R = R′ = Me, 5c; R = R′ = Et, 5d; R = H, R′ = 2-Me-C6H4, 5e) and equimolar amounts of C(R)(R′)Cl2. Analogously, WOCl3[κ2- {1,2-C6H4(O)(CHO)}], 5f, and 1,2-C6H 4(OH)(CHCl2) were obtained from 1 and salicylaldehyde. The 1:1 reaction of 1 with acetone in CH2Cl2 resulted in the clean formation of WOCl4 and 2,2-dichloropropane. Compounds 5a,b,f were isolated as crystalline solids, whereas 5c,d,e could be detected by solution NMR only. The interaction of 1/CH2Cl2 with isatin, in a 1:1 molar ratio, revealed to be a new, convenient route for the synthesis of 3,3-dichloro-2,3-dihydro-1H-indol-2-one, 6. The 1:1 reactions of 1 with R′OCH(R)CO2Me (R = H, R′ = Me; R = Me, R′ = H) in a chlorinated solvent afforded the tungsten(v) adducts WCl 4[κ2-OCH(R)CO2Me] (R = H, 7a; R = Me, 7b). 1/CH2Cl2 reacted sluggishly with equimolar quantities of trans-(CO2Et)CHCH(CO2Et) and CH2(CO 2Me)2 to give, respectively, the W(iv) derivatives WCl4[κ2-CH2(CO2Me) 2], 8a, and [WCl4-κ2-{trans-(CO 2Et)CHCH (CO2Et)}]n, 8b, in about 70% yields. The molecular structures of 2a, 3, 4, 5a, 5f, 7a and 7b were ascertained by X-ray diffraction studies.