Di -addition

Limited data are available on the reaction of diaJdehydes with dinitromethane. Succindialdehyde and glyoxal gave the diaddition products, l,l,6,6-tetranitrohexane-2,5-diol (106) and 1,1,4,4-tetra-nitrobutane-2,3-diol (107), respectively 56). Whether this is due to the low tendency of these dialdehydes to form cyclization products — reaction of glyoxal with nitromethane can give di-addition 57) and cyclization products 58) — or is a general behavior of dinitromethane is not yet apparent. 

Nonconjugated dienes react as expected to give mono- or di-addition products (equations 96-98).70,144,145 Norbomadiene also produces nortricyclyl product (equation 99).71... 

The a-oxidation of aldehydes was later further extended to the use of ketones as nucleophiles. In order to develop this reaction into a useful process, a considerable effort was made to optimize the reaction conditions as several different problems arose these included a lower reaction rate and yields because of the formation of the di-addition product at the two enolizable carbon atoms and lower 0/N-selectivity. Hayashi et al. [16a] and Cordova et al. [16c] partly solved these problems by using a relatively large excess of ketone and by applying the slow addition method leading to good chemical yields (44-91%), with near-enantiopure products being obtained (96-99% ee). 

The transition-metal-catalyzed diboration of alkynes can be directed to give highly selective di-addition yielding 1,2-diborylated olefins (equation 24). Depending on the catalyst. 

The cycloaddition of phenyl azide to the alkynic Grignard (249) provides an interesting variant of this approach (67Z0R968>, as the intermediate can in turn be carboxylated with CO2 to (250). Alkadijmes can serve in a successful approach to control mono- or di-addition (58CB1841). The products are (251) and (252). 

Synthesis from Glyoxal.—Glyoxal, being a di-aldehyde, (p. 261), forms a di-addition product with hydrogen cyanide, HCN, and this di-cyanide addition product hydrolyzes and yields tartaric acid. The reaction may be expressed as follows,... 

Chemisorption of cyclohexane, n-hexane, and 2,3-dimethylbutane on small platinum clusters has been reported to be quite facile. These species also readily exhibit sequential reactions. Even the platinum atom forms a di-addition product with cyclohexane. The first report of this reaction utilized high-fluence 6.42-eV photons to ionize the reaction products. The resultant mass spectra showed extensive hydrogen loss, and a C H ratio near 1 was found for most product ions (Fig. 2 in Trevor et al. ). As discussed above, extensive hydrogen loss may be due to laser cooking during ionization. More recent experiments, which utilized low-fluence 7.87-eV ionizing pho-... 

Fig. 12 Interface reactive two-component injection moulding - bond strength in dependence on the type of diisocyanate and TPU elastomer. Bond strength between PA-6/TPU. PA-6 Ultramid B3S TPU Elastollan 1185A, Elastolian B 85A, Eiastollan C 85A, Elastollan C 60D. Modifiers diisocyanates MDI, IPDI, IPDI-Uretdion, PBDI, Oligomer-TDI-DI. Addition of 1 up to 5 wt% ...

Some of the metals we have been discussing can be used for the simultaneous di-addition of an alkyl or aryl group and a metal to an alkyne.30 This process is called carbometallation and involves particularly Li, Mg, Al, Cu, and Zn. 

A variety of other factors affect reactivity of ethers in additions to fluorinated alkenes and we will gradually explore these. First, a process that was outlined by Muramatsu y), many years ago a 1,5—intramolecular hydrogen transfer occurs from the intermediate radical [1] and ultimately leads to a di—addition product [2]. 

The Cr(II) amine complex, formed by rapid addition of an aqueous solution of Cr(Il) perchlorate to a cold solution of ethylenediamine or Et3N in DMF, reduces terminal and alkylphenylacetylene, but not dialkylacetylenes to the corresponding olefin with a high selectivity for the cis-isomer. Propargyl alcohols undergo facile reduction, but with stereoselectivity, the [Cr -ethylenediamine] complex favoring tranj-addition, whereas [Cr -NEt3] favors di-addition °. Tranj-additions is the exclusive pathway in the absence of amine, e.g. ... 

When organoaluminum hydrides react with acetylenes, a variety of products is formed not only mono- and di-addition to the triple bond, but also replacement of the ethynyl-hydrogen with removal of hydrogen, take place.254 The last of these reactions, which is a metallation, becomes the main reaction when a complex aluminum hydride MA1H4 (M = Li, Na, or K) reacts with an acetylene, so that complex acetylenylaluminates MA1(C =CR)4 can be obtained in this way.255... 

Mono- and di-addition products can be obtained from diolefins.330... 

Aktivierte 1,2-disubstituierte Acetylene wie Acetylendicarbonsaure-diethy tester reagieren mit einem UberschuB Thioessigsaure leicht unter Di-Addition zu einer Mischung von me so- und d,l-2,3-Bis-[acetylthio]-bernsteinsaure-dimethylester (15%)161 ... 

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