New stereochemical outcomes in the cycloaddition of acid halides or equivalents to cinnamylideneamines: A concise new approach to 4-acetoxyazetidin-2-ones.
Fluoride ion mediated peterson alkenation of bis(trimethylsilyl)methylimines: a novel synthesis of 2-aza-1,3-dienes and N-vinyl-β-lactams
作者:Juan Lasarte、Claudio Palomo、Jean P. Picard、Jacques Dunogues、Jesús M. Aizpurua
DOI:10.1039/c39890000072
日期:——
The formation of bis(trimethylsily)methylimines and their transformation into aza-1,3-dienes by means of a fluoride-induced catalytic Peterson alkenation is reported; when the procedure was applied to N-[bis(trimethylsilyl)methyl]-azetidin-2-ones, a wide range of N-vinyl derivatives were obtained in high yields.
Stereocontrolled synthesis of N-vinyl-, N-(1'-propenyl)-, and N-unsubstituted-.beta.-lactams from 2-aza-1,3-butadienes via the Staudinger reaction
作者:Gunda I. Georg、Ping He、Joydeep Kant、Zhin Jun Wu
DOI:10.1021/jo00073a042
日期:1993.10
2-Aza-1,3-butadienes 2 and 5 were synthesized in good yields and on a large scale. Reaction of 2 and 5 with acid chlorides in the presence of triethylamine (Staudinger reaction) resulted in the high-yielding formation of N-vinyl- and N-(1'-propenyl)-beta-lactams. Excellent cis-stereoselectivity was observed in the reaction of 2-aza-1,3-butadienes 2 and 5 with Bose-Evans ketenes and Sheehan ketenes, whereas reaction with a Moore ketene gave, as expected, a trans beta-lactam. N-Formyl, N-vinyl, and N-(1'-propenyl) groups at the beta-lactam nitrogen could be cleaved oxidatively in one step and in good yields by treatment with potassium permanganate. It was also found that the N-vinyl group can be removed successfully under hydrolytic, conditions to yield N-unsubstituted-beta-lactams.