Carbonyl compounds reaction with diazoalkanes

The problem of distinguishing between carbenoid and carbonium ion mechanisms of decomposition of diazoalkanes in protic media arises also in interpreting the base-induced decomposition of tosylhydrazones. In the original procedure for this widely-used reaction (W. R. Bamford and Stevens, 1952), the tosylhydrazone of a carbonyl compound is treated with the sodium salt of ethylene glycol in refluxing glycol. A mixture of olefins and alkoxyethanol is produced (equation 6). Many... 

Two types of products are generally obtained by reaction of ketones with diazoalkanes a homologous carbonyl compound and a small amount of oxirane. The reaction scheme is presented in Eq. 85. 

The high nucleophilicity of a-selenoalkyllithiums towards carbonyl conqiounds, even those that are the most hindered or enolizable, such as 2,2,6-trimethyl- and 2,2,6,6-tetramethyl-cyclohexanone (Schemes 113 and 164), di-t-butyl ketone, pennethylcyclobutanone, peimethylcyclopenta-none (Schemes 113 and 187) °- and deoxybenzoin (Schemes 115, 116 and i65y 4 49 23 iqws the synthesis of related alkenes, epoxides and rearranged ketones which are not available from the same carbonyl compounds on reaction with phosphorus or sulfur ylides - or diazoalkanes. ... 

Condensation with carbonyl compounds. Formation of epoxides from aldehydes by reaction with sulfonium ylides is subject to asymmetric induction. The latter species have been generated from 91, 92, and 93, and also those derived from monoterpenes, e.g., 94 " and 95.- Of course the ylides can be obtained in situ by deprotonation of sulfonium salts or copper-catalyzed decomposition of diazoalkanes (with the carbenoids trapped by the sulfides). 

The twofold extrusion of nitrogen and sulfur and selenium and sulfur from 1-thia- and l-selena-3,4-diazolines(77), readily available from the reaction of diazoalkanes with thio- and selenaketones, respectively, as well as from the reductive coupling of carbonyl compounds such as 78, is the preferred method for preparation of olefins of type I and II (98,99). Examples of the extrusion method, developed by Barton (100), and the McMurry reaction (101) are given in Scheme 1. 

Homologation of carbonyl compounds. The very bulky organoaluminums promote reaction of aldehydes and ketones with diazoalkanes. Aldehydes afford ketones. 

Table 2-1 shows ten types of synthetic process. Methods 1 and 2 are based on aliphatic amines, 3-5 on derivatives of carbonyl compounds, 6 on hydrocarbons with a relatively acidic CH proton, and 7-9 are reactions of diazoalkanes obtained by one of the types 1-6. Reaction 10 involves a diazo ketone, which can be obtained by reaction 9, the first step of the Arndt-Eistert synthesis. 

Na2Mo02 2H2O) and sodium methylamino- or ethylamino-dithiocarbamate. In THF, the Mo compound is treated with various simple diazoalkanes, e.g., phenyl-, diphenyl-, methylphenyl-, and secondary alkyl-diazomethanes. In this reaction (10-21), metalloazines of type 10.54 are formed as yellow crystals in a broad spectrum of yields up to 99%. The ratio of (Z)- to ( )-isomers was determined based on NMR spectroscopy. These metalloazines behave as active carbonyl equivalents in a Wittig-type reaction with phosphoranes (10-22) and form the corresponding ethene derivatives. 

The reaction of diazoalkanes with carbonyl-containing compounds dates back to observations made by Buchner and Curtius as early as 1885 [56]. Although others examined this novel reactivity pattern [57,58], Schlotterbeck is largely credited with uncovering the merger of aldehydes and diazoalkanes in 1907 [59, 60]. Schlotterbeck was able to confirm by careful experimentation that various aliphatic aldehydes afforded the corresponding methyl ketones when treated with diazomethane. The reaction of aldehydes with diazomethane to form methyl ketones (Scheme 3) later became known as the Buchner-Curtius—Schlotterbeck reaction [61]. Application of this chain elongation to ketmies and eventually cycloalkanones did not come until several decades later and required a critical new discovery. 

The reaction of diazomethane with a,p-xmsaturated carbonyl compounds under classical protic conditions has been shown to produce pyrazoline products arising from 1,3-dipolar cycloaddition [3, 4]. Limited examples of a,p-xmsaturated carbonyl substrates undergoing ring expansion in the presence of Lewis acid promoters have been reported. It was not until the introduction of Lewis acids for diazoalkane ring expansion that these types of substrates were even reactive. In Drege s... 

Dipolar cycloaddition reactions constitute a powerful and convergent tool for the preparation of various heterocyclic compounds, which have been widely applied in the synthesis of numerous natural products, pharmaceuticals, and functional materials. The chemistry of 1,3-dipolar cycloaddtion reactions has been well documented in a number of reviews [3]. In this section the focus is on transition-metal-mediated 1,3-dipolar cycloaddition reactions with some important 1,3-dipoles, including azides, diazoalkanes, carbonyl ylides, and azomethine ylides, rather than a full review of the reactions of all types of 1,3-dipoles. 

Methylene compounds with two neighboring sulfone groups can also be used for diazo transfer reactions as shown in 1964 by Klages and Bott. They obtained diazobis(ethylsulfonyl)methane (2.127) and diazobis[(diethylamino)sulfonyl)]me-thane (2.128) in aqueous ethanol and NaOH at - 5 °C and in ether with methyl-lithium at room temperature, respectively. In a similar way, methylene compounds activated by a sulfone and a carbonyl group, yield diazo derivatives, e.g., 1-diazo-l-(4 -toluene)sulfonyl propan-2-one (2.129, van Leusen et al., 1965), 2-diazo-2-(me-thylsulfonyl)-2-phenylethan-l-one (2.130, Illger et al., 1972), l-diazo-l-[(4 -nitro-phenyl)sulfonyl)]propan-2-one (2.131, Hodson et al., 1968), and other a-diazo-)ff-oxo-)ff -sulfonyl compounds (Monteiro, 1987 b) and similar diazoalkanes (van Leusen and Strating, 1988). 

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