Halides aldehydes, synthesis with

SOMMELET Aldehyde synthesis Aldehyde synthesis from primary alkyl halides with hexamethylene tetramine. 

The (V-methyldihydrodithiazine 125 has also been used as an effective formyl anion equivalent for reaction with alkyl halides, aldehydes, and ketones (77JOC393). In this case there is exclusive alkylation between the two sulfur atoms, and hydrolysis to give the aldehyde products is considerably easier than for dithianes. However, attempts to achieve a second alkylation at C2 were unsuccessful, thus ruling out the use of this system as an acyl anion equivalent for synthesis of ketones. Despite this limitation, the compound has found some use in synthesis (82TL4995). 

Nozaki-Hiyama-Kishi (NHK) reactions215,216 are well known and often employed as a useful method for the synthesis of natural products by coupling of allyl, alkenyl, alkynyl, and aryl halides or triflates with aldehydes. The organochromium reagents are prepared from the corresponding halides or triflates and chromium(ll) chloride, and are employed in polar aprotic solvents (THF, DMF, DMSO, etc.). Subsequently, it was found that nickel salts exhibited a significant catalytic effect on the formation of the C-Cr bond217,218 (Equation (19)). 

Koch aldehyde synthesis) introduces the H-—C=0 function into reactive aromatic compounds such as 2-naphthalenol. The necessary reagents are HCN, HCl, and a metal-halide catalyst (ZnCI2 or AICI3), and the initial product must be treated with... 

Hydrolysis yields the terminal acetylene (3) carbonation yields the propargylic acid (4). Synthesis of a wide variety of acetylenes is possible by the reaction of the intermediate lithium acetylides with other electrophiles (alkyl halides, aldehydes, ketones). 

The tin enolates are useful in organic synthesis as a mild source of the nucleophilic enolate group in its reaction with alkyl or acyl halides, aldehydes or enones. The tin enolates are less basic than the lithium enolates, and more reactive though rather less easy to handle than the silicon enolates.105-113... 

Aldehyde synthesis.2 The carbanion generated from this reagent (1) reacts with an alkyl halide to give an aldehyde dimethyl mercaptal S-oxide (2). This product is easily... 

Krohnke aldehyde synthesis. Transformation of benzyl halides into aldehydes via their pyri-dinium salts which, on treatment with p-nitrosodi-methylaniline, give nitrones. Hydrolysis of the nitrones yields aldehydes. 

Reactions alkylations, reactions with epoxides and aldehydes, conjugate additions Heterocyclic synthesis with allyl silanes Reactions with Co-stabilised cations An Allyl Dianion The Role of Tin in Anion Formation Halide Exchange with Chelation Indium Allyls Allyl Anions by Deprotonation The synthesis ofall-trans dienes The synthesis ofall-trans retinol... 

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