Novel cationic carbene complex lacking heteroatom stabilization

Preparation and reactions of alkyl- and arylpentacarbonyltungsten anions

“…WCHCeHs 3. The preparation of carbene complexes by hydride abstraction with (CeHsHC4 has been reported 32. The reaction of 12m with (C6Hj)3C+BF4_ occurs in CH2C12 at -78 °C.…”

Competitive processes in the hydration of dicarbonyl .eta.5-(cyclopentadienyl) alleneiron cations

“…Thus, rearrange-FpCH2 Fp FpCHPh 8 9 10 ment of the allyl alcohol (6) takes place rapidly in an aqueous-acetone solution 0.2 M in HBF4, and formation of 4 and 5 from 3 occurs with equal ease in 0.06 M aqueous-acetone solutions of the salt, which therefore cannot be more than 0.06 M in HBF4. Hydrolytic rearrangement of 3 takes place slowly even when the salt is suspended in an aqueous phosphate solution buffered to pH 3.3. With these considerations in mind, we undertook an examination of the hydrolysis of 3 in aqueous acetic acid-sodium acetate solutions, under conditions which would preclude the rapid formation of 7, but would allow reversible formation of the acetate (11) and hydrolysis of the more reactive enol acetate intermediate (12). These reactions are summarized below.…”

“…The crude product, obtained in 53% yield, contained <10% of the undesired aldehyde. Similarly, treatment of the allyl acetate (11) under these conditions converted it in 73% yield to the ketone (4), containing 10% of the isomeric aldehyde.…”

“…The solution was filtered under nitrogen through a short column of activity III alumina and the solvent was evaporated to give 0.060 (70%) of Fp(allenyl) (18). 6 Synthesis of Fp(AcOCH2CCH2) (11). The aliene complex (3) was added to a methylene chloride solution (5 mL) of benzyltrimethylammonium acetate (0.15 g, 0.70 mmol), prepared from benzyltrimethylammonium tetrafluoroborate by exchange on Dowex 1.…”

“…The ketone component similarly showed resonances at 4.76 (Cp), 1.92 (CH3CO), and 1.60 (CH2CO) in a ratio of 5.0:1.9:1.9. Conversion of Fp(AcOCH2CCH2) (11) to FpCH2COCH3 (4). The acetate (0.050 g, 0.2 mmol) was taken up in 1 mL of acetic acid containing 0.1 mL of water and 0.1 g of potassium acetate.…”