Allenes amination

Note 2. The further conversion into the yneamine CH3CEC-Morph is stopped almost completely by the addition of HO-tert.-Ci,Hg which forms the 1 1 complex with KO-tert.-CgHg. If the isomerization with KO-tert.-CgHg is carried out in DMSO, an equilibrium mixture of about 80 of the allenic amine and 20% of the yneamine is formed after 1-2 min at 30°C. 

An analogous catalytic system has been applied to the IH of y- and 5-allenic amines which cyclize smoothly in the 5-Exo-Trig or 6-Exo-Trig mode, giving vinylpyrrolidines and vinylpiperidines, respectively (Eq. 4.92) [313]. 

IH of allenic amines also occurs in the presence of silver salts. IH of a-allenic amines proceeds in good yields in the presence of AgBp4 and provides a useful method for 3-pyrrolines synthesis via Endo-Trig processes (Eq. 4.93) [314]. 

Although less efficient (TOP = 0.04 h ), similar IH ofofy- and 5-allenic amines in the presence of AgNOj give 2-alkenylpyrrolidines and 2-alkenylpiperidines, respectively (5 [or 6]-Exo-Trig processes) [315]. These reactions have been applied to the synthesis of ( )-pinidine [316] and -) R) coniine [317]. 

Inhibition of monoamine oxidase B by allenic amines R. A. Smith, R. L. White,... 

Ultrasound irradiation of mixtures of amines RNH2 (R = PI1CH2, Ph or Ar) and methyl pyruvate results in the 3-pyrrolin-2-ones 322377. The silver tetrafluoroborate-catalysed cyclization of the allenic amines 323 leads either to a pyrroline 324 or tetrahydropyridine 325, depending on the structure of the amine. The former is formed from 323 (R = H), the latter from 323 (R = Me)378. 

If still some allenic amine is present, the product is heated again at 120-130 C. 

Successful allylzincations of the terminal double bond of a-allenic amines have also been reported (equation 56)88. 

Amino cycttzation.1 In the presence of AgOTf or AgBF4 allenic amines cyclize to 2-substituted pyrrolidines. A stereogenic center adjacent to N can induce asymmetric induction, which is dependent on the concentration of Ag(I). 

The corresponding nitrogen-containing heterocycles are accessible by silver-catalyzed cyclization of allenic amines, amides, or oximes.334 Thus, Dieter and Yu335 have reported the efficient transformation of various a-aminoallenes 397 or 399 into mono- or bicyclic 3-pyrrolines 398 or 400 in the presence of AgN03 (Scheme 116). Unfortunately, a rather high catalyst loading was required. 

Less hindered methyl and alkyl halides react at the a-carbon of 42 but the resulting allenic amines are too unstable. By chosing bulkier diisopropylamino and especially tetramethylpiperidino groups, selective /-alkylations can be effected (77)ll7). 

Sahlberg, C. and Claesson, A.. Allenes and acetylenes. XXIV. Synthesis of a-allenic amines by organocuprate reactions of acetylenic aminoethers. Acta Chem. Scand., B.36. 179, 1982. 

Bntadien 3-Methyl-2-(methyl-amino-methyl)- E18, 1032 (Allen + Amin)... 

Benzyl-ethyl-isopropyl- IV/ld, 358 Bis-[3-methyl-2-methylen-3-butenyl]-E18, 1032 (Allen + Amin) Dipropyl-phenyl- XI/1, 216 Hexyl-phenyl- XI/1, 947 Anilln... 

When the chiral allenic amine 1 was cyclized using silver tetrafluoroborate, transfer of chirality occurred from the allenic moiety to the C-2 stereogenic center, as determined by conversion of 2 into the diastcrcomeric mixture of the (+)-(5)-0-methylmandelic amides of the debenzylated product. The high asymmetric induction was ascribed to the formation of a dissymmetric silver-allene complex229. 

---