The cationic tetra-coordinated 16 electron complex [Ir(trop 2 dach)] þ OTf À (1) where (OTf À ¼ CF 3 SO 3
À) and the neutral amine amido complex [Ir(trop 2 dach-1H)] (2) were isolated and structurally characterized. The NH function in 1 is easily deprotonated (pK a DMSO ¼ 10.5) to yield the amino amido complex [Ir(trop 2 dach-1H)] (2), which is deprotonated at pK a DMSO ¼ 19.6 to the anionic di(amido) iridate [Ir(trop 2 dach-2H)] À (3); [(R,R)-top 2 dach stands for the tetrachelating diamino diolefin ligand (R,R)-N,N 0 -bis(5Hdibenzo[a,d]cyclohepten-5-yl)-1,2-diaminocyclohexane; (R,R)-top 2 dach-1H and (R,R)-top 2 dach-2H indicate the mono and double deprotonated form]. Complex 3 is easily oxidized by 1,4-benzoquinone (BQ) to the neutral iridium aminyl radical complex [Ir(trop 2 dach-2H)](4). In combination with BQ as hydrogen acceptor and catalytic amounts of base, 4 serves as catalyst in the highly efficient dehydrogenation of functionalized primary alcohols to the corresponding aldehydes, RCH 2 OH þ BQ / RCH]O þ H 2 BQ (H 2 BQ ¼ catechol). Alcohols like geraniol and retinol are rapidly converted to geranial and retinal, while the conversion of sterically hindered alcohols like lavandulol is slower and the primary product, lavandulal, isomerizes to isolavandulal in a classical base-catalyzed reaction. To cite this article: N.
The seeds of HERNANDIA SONORA L. (Hernandiaceae) yielded eight lignans. Five of them have already been described from other species of the HERNANDIA genus, namely podophyllotoxin ( 1), picropodophyllin ( 2), deoxypodophyllotoxin ( 3), hernandin ( 4), and podophyllotoxin acetate ( 5). 5-Methoxypodophyllotoxin ( 6), 5-methoxypodophyllotoxin acetate ( 7), and a dibenzylbutyrolactone ( 8) are new. Their structures are presented in this publication.
Publication details, including instructions for authors and subscription information:ABSTRACT The chemical composition of the essential oils of the leaves and stem bark of Canella winterana (L.) Gaertn. (Canellaceae), was investigated by GC and GC/MS. In
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