Organoselenium Chemistry. Preparation of Allyl and Homoallyl Amines by Aminomethylation of Phenylseleno‐Substituted Allyl Tin Reagents

Metalation of methallyl phenyl selenide, allyl phenyl selenide, and methallyl phenyl sulfide followed by tri‐n‐butylstannylation gave exclusively the γ‐stannylated sulfide or selenide (e.g., 1‐phenylseleno‐2‐methyl‐3‐tri‐n‐butylstannyl‐1‐propene ( 5 )). Compound 5 reacts with a series of immonium electrophiles to give products of aminomethylation α‐ to selenium. Electrophiles have included N‐(bromomethyl)phthalimide/ZnBr 2 , Eschenmoser salt (dimethylmethyleneammonium iodide), and Mannich reagents generated in situ from diethylamine, piperidine, isopropyl sarcosinate and benzylmethylamine. The selenide from the last of these amines (N, 3‐dimethyl‐N‐benzyl‐2‐phenylseleno‐3‐butenamine, 10 ) has been subjected to further transformations as follows: (1) treatment of 10 with trimethylstannyllithium results in replacement of phenylseleno by stannyl; this allyltin ( 11 ) can then again be aminomethylated giving compound 12 or 13 ; (2) oxidation of 10 gives amino alcohol 14 by [2, 3] sigmatropic rearrangement of the allyl selenoxide; (3) photolysis of 10 results in 1,3‐rearrangement of the phenylseleno group; oxidative rearrangement of this allyl selenide gives amino alcohol 16 . The phthalimidomethylation product ( 6 ) is converted to a precursor for the side chain of the cytokinin zeatin by oxidation and [2, 3] sigmatropic rearrangement.