Ketones, alkynic

Sulfitation and Bisulfitation of Unsaturated Hydrocarbons. Sulfites and bisulfites react with compounds such as olefins, epoxides, aldehydes, ketones, alkynes, a2iridines, and episulftdes to give aHphatic sulfonates or hydroxysulfonates. These compounds can be used as intermediates in the synthesis of a variety of organic compounds. 

The addition of amines to electron-poor alkynes leads to the formation of enamines (Entry 11, Table 10.6). These acceptor-substituted enamines are more stable towards hydrolysis than enamines derived from unsubstituted ketones. Alkynes devoid of electron-withdrawing groups do not react smoothly with amines, and usually require Hg(II) catalysis to be converted to resin-bound enamines (Entry 12, Table 10.6). 

Sml2 -promoted, intramolecular ketone/alkyne couplings were reported in 1990 (equation 32)92. Yields were low (30-50%) for unactivated alkynes (Y = H or CH3), but improved to 50-75% when Y = Si(CH3)3, Ph or CC Et. Also, yields were typically much better for ketones than for aldehydes. 

A nickel-catalysed alkyne insertion between the carbonyl carbon and the -carbon of the cyclobutanone was achieved by combining a ketone-alkyne coupling reaction with a /3-carbon elimination process (Scheme 79).121 The reaction uses cyclobutanones as a four-carbon unit and provides access to substituted cyclohexenones. 

A number of structurally diverse ketones have been reduced using BINAL-H. Some of the results are summarized in Table 1. Aryl alkyl ketones, alkynic ketones, and a, -unsaturated ketones are reduced to alcohols with good to excellent % ee, while aliphatic ketones give products with lower optical purities. The asymmetric reduction of a number of acylstannanes with (7) gives synthetically valuable a-alkoxystannanes with high optical purities after protection of the initially formed unstable alcohols as their MOM or BOM ethers. ... 

Alkynyl ketones. alkynes in MeCN at ro corresponding propargy of an M(acac)j, where 1 the reaction. 

Organotitanium reaga 3-Hydroxy aUehyd ethers of aldehydes fca should be emphasized ill In this method, the dono p-Alkenyl ketones. alkynes with i-PrMgO Li2Cu(CN)Cl2. 

Alkynes also imdergo acid-catalyzed hydration to yield ketones. Alkynes substituted with alkoxy or phenoxy groups undergo hydration readily, and butyl acetate was obtained by heating butoxyacetylene in distilled water... 

Functional groups with double or triple bonds—alkenes, aldehydes, ketones, alkynes, and nitriles—generally take part in addition reactions. 

Reduction of a variety of organic functional groups has long been carried out using ammonia solutions of alkali metals (Birch and SubbaRao, 1972). Given the strongly electropositive character of lanthanides such as ytterbium (which features a 4f 6s electron configuration), it follows that ytterbium/ammonia solutions should convert a,i8-unsatiu ated ketones to saturated ketones, alkynes to trans-alkenes and aromatics to 1,4-dihydroaromatics (White and Larson, 1978). 

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