Aldehydes in additions

Substituted amino naphthols were synthesized with reactions of 1-naphthols and the appropriate aldehydes. Some new 2,4-disubstituted-3,4-dihydro-2/f-naphth [i,2-e][i,i]oxazines that are expected to show biological activities were obtained by the ring-closure reactions with these aminonaphthols and various aldehydes. In addition, substituted-1,3-amino-hydroxy compounds, 2, can be used in chiral ligands synthesis. 

Glutaryl dichloride undergoes reduction at mercury to give 5-chlorovalerolactone and valerolactone a polymeric solid, possibly X[(CH2)3CHCl-0-C=0] (CH2)3X (whereX = CHO or CO2H), is additionally produced [73]. Heptanoyl chloride [71], trimethylacetyl chloride [74], and cyclo-hexanecarbonyl chloride [75] can be reduced at carbon or mercury cathodes to form the corresponding aldehydes in addition, the anhydride (and sometimes... 

Several acyl silanes have been prepared by the silylation of metalloaldimines followed by hydrolysis (Scheme 29)108,109. One limitation of this scheme is the ready decomposition of the aldimine to give aldehyde in addition to acyl silane in approximately equal amounts. 

The green side of the perfume which is less pronounced than in Fidji, and more floral, is based on phenylacetaldehyde and cA-3-hexenyl acetate with perhaps a trace of galbanum. Narcisse absolute may also be used. Other materials that add to the building up of the white flower character are Lilial and cyclamen aldehyde in addition to the hydroxycitronellal and Lyral. The tuberose character can be given by the use of the Schiff base derived from methyl anthranilate and Helional, or by the direct addition of methyl anthranilate. The mossy side of the perfume is represented by Evemyl. 

Finally, formation of 0-(2,3,4,5,6-pentafluorobenzyl)-hydroxylamine (PFBOA) derivatives and analysis by GC-Mass Spectrometry (GC-MS) and GC-Electron-Capture Detection (GC-ECD) appears to be a promising technique, de Revel and Bertrand (42, 43) used PFBOA derivatization to analyze a number of saturated and unsaturated aldehydes in wines, however, high concentrations of acetaldehyde made accurate quantitation of the other aldehydes present in lower concentrations difficult, depending on the wine matrix the aldehydes were not always well separated from other chromatographic peaks pH conditions for the derivatization were not specified and removal of excess PFBOA by acidification caused the partial loss of some aldehydes. In addition, no specific information regarding derivatization efficiency and recovery, or absolute limits of detection and quantitation were reported by these authors. 

In complex examples, high levels of stereodifferentiation require the consideration of the conjoined influences of a-asymmetry in the allylstannane, and chirality of the starting aldehyde, in addition to the choice of auxiliary 1 (eq 10). ... 

We shall base our remarks in this paper principally on two examples 1. Ethanal (acetaldehyde), because it is the most thoroughly investigated aldehyde in addition, it is the only aldehyde whose oxidation has been studied both in the vapor and in liquid phases. 

The use of sulfur in the Peterson reaction can be extended to the optically pure lithio anion of S phe-nyl-S-(trimethylsilyl)tnethylW-tosylsulfoxiniine (330 equation 76). Unlike most Peterson alkenations t reaction is selective for the formation of the ( )-alkene isomer (331) with aldehydes. In addition, the stereochemistry of the sulfoximine is maintained. 

Aldehydes may be converted to ( )-alkenyl halides by the reaction of CrCh with a haloform in THF. The highest overall yields for the conversion were with iodoform, but somewhat higher (E) (Z) ratios were observed with bromoform or chloroform. Other low-valent metals, such as tin, zinc, manganese and vanadium, were ineffective. As the examples in Table 19 indicate, the reaction is selective for the ( )-isomer, except in the case of an a,3-unsaturated aldehyde. In addition, the reaction with ketones is sufficiently slow for chemoselectivity to be observed for mixed substrates. 

Additions to enones, e.g. 115 generally occur in the Michael sense giving 8,e-unsaturated enones33 such as 116. Acetals 118 can replace aldehydes in additions with allylic transposition34 as in 117 to 119 and acylation occurs with acid chlorides as in the synthesis of the terpene artemisia ketone 122 from two C5 units with at least a passing resemblance to the biosynthesis of this irregular terpene.20,35... 

Finally we ll have a quick look at how combinations of these methods have been applied. In the aldol reactions we have looked at so far there has been no chirality at the start. Both the aldehyde and the enolate have been achiral species that have reacted in a stereoselective way to give a particular diastereomer. With the aldol reaction there is a lot of opportunity to introduce aspects of chirality. The enolate could be chiral as could the aldehyde. In addition to this, the whole reaction could be mediated by a chiral catalyst. Although chiral enolates are most commonly associated with asymmetric methods (most famously the method of Evans in Chapter 27) it is important to remember that the components could just as easily be chiral and racemic. The diastereoselectivity that allows the Evans s chemistry to work with optically pure materials will operate whether the auxiliary is optically pure or not. 

As previously discussed two modes of addition (endo and exo) are possible for the orientation of the diene with respect to the aldehyde. In addition to these orientations are preferences for a particular diastereofacial selectivity (CF, ACF) for reactions with chiral aldehydes. A summary of these relationships and how the diastereofacial selectivity can be controlled by use of different Lewis acid catalysts is given in Table IS and Scheme 19. 

In a companion study, M. Palma et al. studied the extraction of grape seeds with pure SF CO2 and analyzed the derivatized extracts by GC-MS. These extracts were found to contain volatiles such as aliphatic aldehydes in addition to fatty acids and sterols. Even though we used similar conditions for our SF extraction and GC-MS analysis, we were unable to detect any similar volatile compounds. To further investigate the presence of volatiles in the cranberry seed extract, we adapted a solid phase microextraction (SPME) method from the work of Jelen et al. who had earlier developed it for the characterization of volatile compounds in different vegetable oils. SPME followed by gas chromatog[raphy was performed on the headspace of the cranberry seed extract to test for the presence of volatile compounds. The GC trace failed to show the elution of any components for either the SF or Soxhlet extract. 

Mansuy, D., J. Leclaire, M. Fontecave, and M. Momenteau (1984). Oxidation of monosubstituted olefins by cytochromes P450 and heme models Evidence for the formation of aldehydes in addition to epoxides and allylic alcohols. Biochem. Biophys. Res. Commun. 119, 319—325. 

Essentially, we have proposed that ozonide (5) is formed not only by the Criegee mechanism but also by reaction of the molozonide with aldehyde. Thus, a competition exists between molozonide fragmentation and molozonide reaction with aldehyde. In addition, ozonide may also be formed by the reaction of molozonide with zwitterion followed by regeneration of a new zwitterion (Reaction 2). As yet we have no evi-... 

The present preparation illustrates a general and convenient method for the Iraws-iodopropenylation of an alkyl halide. The iodopropenyl-ated material is not usually stable but is a useful synthetic intermediate. For example, it forms a stable crystalline triphenylphosphonium salt for use in the Wittig reaction, and under Kornblum reaction conditions (DMSO-NaHCOg, 130°, 3 minutes) it gives an (Fl)-a, 6-unsaturated aldehyde. In addition to the phosphonium salt described in Note 15, the following have been prepared (4- -methoxyphenyl-2-butenyl)-triphenylphosphonium iodide [Phosphonium, [4-(4-methoxyphenyl)-2-butenyl]triphenyl-, iodide], m.p. 123-127° (2-octenyl)triphenyl-phosphonium iodide [Phosphonium, 2-octenyltriphenyl-, iodide], m.p. 98° and (2-octadecenyl[triphenylphosphonium iodide [Phosphonium, 2-octadecenyltriphenyl-, iodide], m.p. 50°. 

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