N-Methylative aziridine ring opening and asymmetric synthesis of MeBmt

Application of Regio‐ and Stereoselective Functional Group Transformations of Chiral Aziridine‐2‐carboxylates

“…This reaction is exemplified by the synthesis of (4 R )‐4‐[( E )‐2‐butenyl]‐4, N‐ dimethyl‐ L ‐threonine (MeBMT), an unusual amino acid constituent of cyclosporine A 39. Initially, the proper backbone was prepared from the highly stereoselective addition of ( E )‐crotylboronate to aziridine‐(2 R )‐carboxaldehyde 3 to give 66 in 87 % yield.…”

Alkylative Aziridine Ring-Opening Reactions

“…This new reaction, called the N -methylative aziridine ring-opening reaction, was used as a key step for the synthesis of various biologically important molecules. We succeeded in making N -methylative aziridine ring-opening reactions with methyl group at the nitrogen coming from MeOTf for the formation of aziridinium ions and subsequent ring opening by nucleophiles, including acetate for MeBMT [ 33 ]; protected p -hydroxyphenyl magnesium bromide for tyroscherin [ 34 , 35 ]; and nitriles for hygroline, pseudohygroline, hygrine [ 36 ] and part of PF-00951966 [ 37 ] ( Figure 1 ). These examples showed the value of N -methylative aziridine ring-opening reactions.…”

Facile Synthesis of N‐Methylated Amino Acids from Chiral Aziridine‐2‐carboxylate

“…Only a change of the acetate source from NaOAc to CsOAc improved the reaction yield up to 90% with a little better ratio of 5:95 (entry 2, Table ). This improvement was expected from our earlier observation that the higher nucleophilicity of acetate gave better ratio . Then we turned our attention to the use of amide 1B instead of ester 1A , which may have a chance to alter the regiochemical pathway with additional advantages of functional diversity.…”