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The current study presents two novel and efficient strategies for the synthesis of N-protected 1-aminoalkylphosphonium salts from readily available substrates. The first one is a one-pot methodology which is based on the three-component coupling reaction of aldehydes with amides, carbamates, lactams, imides, or urea in the presence of triarylphosphonium salt. This approach results in the production of a wide range of structurally diverse N-protected 1-aminoalkylphosphonium salts. The second one is a step-by-step procedure which results in the synthesis of N-protected 1-aminomethylphosphonium salts only, and hence has a limited scope of application. This method is performed in two steps: transformation of amide-type substrates to the corresponding hydroxymethyl derivatives and substitution of the hydroxyl group with triarylphosphine. Both protocols are promising alternatives and complement the hitherto described methodologies. [ABSTRACT FROM AUTHOR]

Catalytic enantioselective Kinugasa reactions between acyclic and, for the first time, cyclic nitrones and terminal alkynes are described herein. A catalytic amount of the readily available PINAP/CuX complexes, generated in situ, efficiently catalyzed the Kinugasa reactions, leading to a series of β-lactams with good enantioselectivities and moderate diastereoselectivities and yields. A broad range of nitrones and terminal alkynes, including the seldom reported alkyl-substituted alkynes, were tolerated under the reaction conditions. Further investigations proved that the PINAP/CuX catalytic system enabled the synthesis of monobactams on the gram scale (without loss of stereoselectivity and yield) and also both enantiomers by the appropriate choice of readily available atropisomeric N-PINAP ligands. [ABSTRACT FROM AUTHOR]

Herein we describe the development and optimization of a two-step procedure for the synthesis of N-protected 1-aminomethylphosphonium salts from imides, amides, carbamates, or lactams. Our "step-by-step" methodology involves the transformation of amide-type substrates to the corresponding hydroxymethyl derivatives, followed by the substitution of the hydroxyl group with a phosphonium moiety. The first step of the described synthesis was conducted based on well-known protocols for hydroxymethylation with formaldehyde or paraformaldehyde. In turn, the second (substitution) stage required optimization studies. In general, reactions of amide, carbamate, and lactam derivatives occurred at a temperature of 70 °C in a relatively short time (1 h). On the other hand, N-hydroxymethylimides reacted with triarylphosphonium salts at a much higher temperature (135 °C) and over longer reaction times (as much as 30 h). However, the proposed strategy is very efficient, especially when NaBr is used as a catalyst. Moreover, a simple work-up procedure involving only crystallization afforded good to excellent yields (up to 99%). [ABSTRACT FROM AUTHOR]

The corresponding starting compounds are electrochemically prepared from N-acyl-amino acids or N-alkylamides. [ABSTRACT FROM AUTHOR]