Alkyl hypophosphites

Scheme 6a) [35], In contrast, Cristau and coworkers followed a different approach for developing a one-pot, three step synthesis of protected phosphinopeptides (Scheme 6b) [43, 44], This protocol involves sequential 0-alkylation of H3PO2, addition of alkyl hypophosphites to imines and finally Michael addition of the resulting DPM-protected aminophosphinates 15 to acrylates. 

More recently, the related indium-mediated radical reactions have been widely studied (Scheme 7.13).19 Indium iodide-mediated radical cyclisation was first reported by Cook et al.20 The indium-mediated 1,4-addition of alkyl radicals to (F)-but-2-enenitrile was investigated by using 1-ethylpiperidinum hypophosphite (EPHP) as a hydrogen donor in aqueous media (Scheme 7.13).21 Atom transfer radical cyclisation and reductive radical cyclisation were studied using indium and iodine.22 Indium mediated alkyl radical addition to dehydroamino acid derivatives was also reported.23 The indium-mediated radical ring expansion of a-halomethyl cyclic (3-keto esters, shown in Scheme 7.13, was achieved in aqueous alcohols.24... 

The use of bis(trimethylsilyl) hypophosphite (phosphonite) continues to provide more unusual compounds. In its reactions with methyl chloroacetate (in the reactant ratio 1 2) in the presence of an HCl acceptor (in this case hexamethyldisiloxane), the initial product 401 undergoes a Michaelis-Arbuzov reaction to yield 402, from which the acid 403 is readily obtainable after standard manipulations The acids 404 and 405 have been prepared using the same methodology, and similar reactions have also been carried out with alkyl alkylphosphinates ... 

Hypochlorous acid (s. a. Hypo-halites) 16,231 19,197 Hypohalites (s. a. Alkyl hypo-halites, Potassium hypo-bromite, — hypochlorite, Sodium hypochlorite, — hypoiodite) 17, 352 Hypophosphite s. Sodium dihydrogen hypophosphite Hypophosphoric acid esters... 

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