A New Class of Redox Isomerization of N-Alkylpropargylamines into N-Alkylideneallylamines Catalyzed by a ReBr(CO)₅/Amine N-oxide System

Abstract

Redox isomerization reaction wherein N-alkylpropargylamines are converted into N-alkylideneallylamines in the presence of rhenium­(I) complexes as catalysts is described. Among the additives tested, certain pyridine N-oxides and tertiary amine N-oxides were effective for the reaction to proceed, and in particular, the use of 2,6-lutidine N-oxides gave the best results. The choice of a diphenylmethyl group as a substituent on the nitrogen atom was key to the success of the reaction, allowing it to reach completion.

Regioselective Cp*Ir(III)-Catalyzed Allylic C–H Sulfamidation of Allylbenzene Derivatives

“…Spectral data match those previously reported in the literature. 38,39 1 H NMR (CDCl 3 , 399 MHz) δ 7.73 (m, 28H), 7.28 (m, 28H), 5.53 (ddd, J = 17.0, 10.3, 6.6 Hz, 9H), 5.45 (dt, J = 15.4, 6.3 Hz, 2H), 5.41−5.28 (m, 3H), 5.14 (dd, J = 15.4, 6.6 Hz, 2H), 5.05 (ddd, J = 15.3, 7.4, 1.7 Hz, 3H), 5.00−4.93 (m, 18 H), 4.58 (d, J = 7.9 Hz, 9H), 4.50 (d, J = 7.6 Hz, 5H), 3.97−3.82 (m, 2H), 3.76 (quint, J = 6.8 Hz, 9H), 3.61 (quint, J = 7.2 Hz, 3H), 2.42 (s, 42H), 1.95−1.80 (m, 5H), 1.56−1.16 (m, 33H), 0.83 (t, J = 7.3 Hz, 42H) ppm.…”

A Highly Stereoselective Redox Isomerization-Reductive Deuteration Sequence of Propargyl Amines to α-Deuterated Amino Acids

“…These base-catalyzed processes likely proceed through allenylamine intermediates, ultimately yielding thermodynamically stable E -configured α,β-unsaturated imines as the final product. Recently, Fukumoto reported an elegant rhenium complex catalyzed redox isomerization of N -alkylpropargylamines to N -alkylideneallylamines via a vinylidenerhenium intermediate (Scheme b) . Despite these significant achievements, the existing protocols are limited to terminal alkynes or result in the formation of E -configured α,β-unsaturated imines.…”

“…Although significant progress has been made in the redox isomerization of propargylic amines, ,, the corresponding transformation of α-alkynyl amino acid derivatives remains unexplored. Therefore, we initially evaluated the redox isomerization of α-phenylethynyl ethyl glycinate 1a (Table ).…”