Esters from trihalides

Orthocarboxylic acid esters from 1,1,1-trihalides CHalg C(OR)3... 

A methyl ester was formed by methanolysis of a trihalide (Equation 32) <2007S225>. Decarboxylation of the /3-ketoacid resulting from hydrolysis has also been reported (Equation 33) <1980LA1917>. A carboxylic acid substituent was reduced to aldehyde with LAH (Equation 34) <1974J(P1)2092>. Thiazine nitrogen probably participates in this reaction. 

A number of boron chemicals are prepared directly from boric acid. These include synthetic inorganic borate salts, boron phosphate, fluoborates, boron trihalides, borate esters, boron carbide, and metal alloys such as ferroboron [11108-67-1]. 

A significant advance in the synthesis of monoorganotin trihalides was the preparation of p-substituted ethyltin trihalides in good yield from the reaction of stannous chloride, hydrogen halides, and CC, 3-unsaturated carbonyl compounds, eg, acrylic esters, in common solvents at room temperature and atmospheric pressure (153,154). The reaction is believed to proceed through a solvated trichlorostannane intermediate (155) ... 

The unsaturated character of these trialkyl esters was shown by the ease with which they were attacked by nitric acid, but still more clearly by the formation, with evolution of heat, of stable crystalline addition compounds when they were mixed with cuprous halides. Thus CuC1.P(OC2H5)3 was described as consisting of colourless crystals melting at 190° to 192° C. and soluble in organic solvents.4 This property they share with phosphine, alkylphosphines and phosphorus trihalides. The phosphoric esters were quite indifferent to cuprous halides. Nor were such addition compounds formed either by phosphorous acid itself or by the dialkyl esters, which may show that the latter compounds have the unsymmetrical formula. Phosphorous acid probably exists in both forms, but first as P(OH)3, i.e. when produced from PC13 and Ha0.5 This may be transformed into the unsym-metrieal form through an addition compound HC1.P(0H)3,4 and probably also exists in the form of complex molecules, such as... 

Tris(organoamino)boranes have been utilized to prepare, in reasonable yields,4,5 mono- and dihalo(organoamino)boranes which are often difficult to obtain by direct amination of the boron trihalides. Carboxylic acids, 1,3-diketones, ketones, and /3-ketoesters have been converted into carboxamides, enamino-ketones, enamines, and j -enamino-amides, respectively, by reaction with an appropriate tris(organoamino)borane under very mild conditions.6 Sulfenamides (R2NSC6H5) have also been prepared in high yield from selected tris(organoamino)boranes and sulfenic esters under relatively mild conditions.7... 

The Fries rearrangement proceeds via ionic intermediates but the exact mechanistic pathway (whether it is inter- or intramolecular) is still under debate. There are many reports in the literature that present evidence to support either of the pathways, but it appears that the exact route depends on the structure of the substrates and the reaction conditions. The scheme depicts the formation of an ortho-acylated phenol from a substituted phenolic ester in the presence of aluminum trihalide catalyst. The photo-Fries rearrangement proceeds via radical intermediates. ... 

Olah, G. A., Karpeles, R., Narang, S. C. 1982. Synthetic methods and reactions 107. Preparation of co-haloalkylcarboxylic acids and esters or related compounds from lactones and boron trihalides. Synthesis 1982 963-965. 

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