Grignard reagents reaction with amino ethers

Miscellaneous Reactions. Sodium bisulfite adds to acetaldehyde to form a white crystalline addition compound, insoluble in ethyl alcohol and ether. This bisulfite addition compound is frequendy used to isolate and purify acetaldehyde, which may be regenerated with dilute acid. Hydrocyanic acid adds to acetaldehyde in the presence of an alkaU catalyst to form cyanohydrin the cyanohydrin may also be prepared from sodium cyanide and the bisulfite addition compound. Acrylonittile [107-13-1] (qv) can be made from acetaldehyde and hydrocyanic acid by heating the cyanohydrin that is formed to 600—700°C (77). Alanine [302-72-7] can be prepared by the reaction of an ammonium salt and an alkaU metal cyanide with acetaldehyde this is a general method for the preparation of a-amino acids called the Strecker amino acids synthesis. Grignard reagents add readily to acetaldehyde, the final product being a secondary alcohol. Thioacetaldehyde [2765-04-0] is formed by reaction of acetaldehyde with hydrogen sulfide thioacetaldehyde polymerizes readily to the trimer. 

As mentioned in Section 10.6.2, synthesis of 1-hydroxyethylene peptides can be initiated by adding a ferf-butoxycarbonyl N-protected a-amino aldehyde to an optically active Grignard reagent (Scheme 7)J11-13 This reaction affords a diastereomeric mixture of the C4 epimers of the hydroxy ether in good yields. In most cases the mixture is enriched in the 45-epimer and the epimers are readily separable. The yields and the ratios of the resulting 45- and 4R-epimers obtained from several examples of this reaction are summarized in Table 1. When this reaction was attempted with the aldehyde prepared from Aa,Ae-bis-tert-butoxycarbonyl-protected Lys, the desired product was not obtained. The anion of the Lys Ne-tert-butoxy-carbonylamino group probably reacts with the aldehyde to form a cyclic aminol that does not... 

To a solution of Grignard reagent prepared from 2-bromoanisole (46.8 g, 250 mmol) and magnesium turnings (6.08 g, 250 mmol) in diethyl ether (150 mb), a solution of D-phenylalanine ethyl ester (9.66 g, 50 mmol) in ether (50 mb) was added in the course of 5 h. The reaction mixture was heated under reflux for 5 h and was then carefully added to dilute hydrochloric acid under cooling. The precipitate was Altered and treated with an aqueous ammonia to give the amino alcohol as white crystals (yield 12.4 g, 68%). A sample recrystallized from cyclohexane showed mp 102-103 °C, [ajp -1-42.5 ° (c 1.00, chloroform). 

The amino alcohol, i -2-amino-l,l-di-(2-octyoxy-5-ferf-butyl-phenyl)-propa-nol, was prepared by the reaction of a Grignard reagent from 2-bromo-4-ferf-butylphenyl octyl ether [35] with D-alanine ethyl ester. The copper complex was prepared in the similar manner as above. In this case, neither the amino alcohol, the Schiff base, nor the copper complex was crystalline. 

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