An Efficient Procedure for Palladium-Catalyzed Hydroformylation of Aryl/Enol Triflates

Palladium‐catalyzed hydroxycarbonylation as the key step in the synthesis of a carbon‐14 labeled Maxi‐K channel blocker

“…The major product of the reaction was the carboxylic acid (6), which was isolated in 15% yield, with the remainder being unreacted bromide and a trace amount of the arene resulting from hydrodehalogenation. As expected, we were able to selectively reduce the aldehyde in the presence of both ketones by heating with sodium triacetoxyborohydride in benzene to obtain the benzylic alcohol (7). However, we required further synthetic steps to obtain our target compound and this led us to pursue a more efficient method for the introduction of the radiolabel.…”

Palladium Catalysts for the Formylation of Vinyl Triflates To Form α,β‐Unsaturated Aldehydes

“…The use of bidentate ligands with diphenylphosphino substituents led to an increase in the yield of the cyclohexenecarbaldehyde to up to 21 %. However, the best results were observed when diphosphine ligands with bulky alkyl substituents were used (Table 1, entries [13][14][15][16]. To explore more thoroughly the potential of bulky bidentate phosphine ligands in the model reaction, we also synthesized new chelating ligands with di-1-adamantylphosphino moieties attached to various backbones (Scheme 2).…”

A CONVENIENT PREPARATION OF SELECTIVELY PROTECTED L-DOPA DERIVATIVES FROM 3-IODO-L-TYROSINE

“…First attempts were made on a fully protected 3-iodo-L-tyrosine (1c), adopting a procedure similar to that developed originally by Kotsuki 13 for aryl triflates and applied successfully by us to the preparation of 4-hydroxymethyl-L-phenylalanine. 12b Reaction of 1c with carbon monoxide and trioctylsilane in the presence of Pd(OAc) 2 /dppp 14 as the catalyst in DMF at 80 C and atmospheric pressure resulted however in premature catalyst decomposition and low conversion.…”

“…13 Triethylsilane has been previously employed as hydride donor in the carbonylation of arenediazonium salts 16 and aryl iodides, 17 but pressurized CO had to be used to obtain satisfactory yields of aldehydes in the former case, while in the carbonylation of ary1 iodides a Pd-Co bimetallic system was investigated and the major products were either benzyl silyl ethers or 1,2-diaryl-1,2-disiloxyethanes. Benzylation of the free phenol was accomplished utilizing Boger's conditions (BnBr/K 2 CO 3 /n-Bu 4 NI/DMF, rt) 9 to minimize possible racemization and provided 2c in near quantitative yield.…”

“…1H, m, a-CH), 5.02 (1H, d, J ¼ 6.9 Hz, NH), 5.17 (2H, s, PhCH 2 O), 7.00 (1H, d, J ¼ 9.0 Hz, ArH), 7.26-7.43 (6H, m, ArH), 7.60 (1H, br, s, ArH),10.52 (1H, s, CHO);13 C NMR d 28.27, 37.40, 52.36, 54.42, 70.61, 80.07, 113.32, 125.00, 127.33, 128.33, 128.76, 128.86, 129.04, 136.04, 136.70, 155.02, 160.20, 172.09, 189.49. Anal.…”