Stereoselective Isomerisation of N-Allyl Aziridines into Geometrically StableZ Enamines by Using Rhodium Hydride Catalysis
作者:Derek S. Tsang、Sharon Yang、France-Aimée Alphonse、Andrei K. Yudin
DOI:10.1002/chem.200701322
日期:2008.1.18
the most likely mechanism of isomerisation would involve a rhodium hydride addition/beta-hydride elimination sequence. We show that the observed selectivity cannot be adequately explained by this pathway and is more consistent with initial CH-activation followed by rearrangement to form a five-membered cyclometallated rhodium intermediate. This intermediate subsequently undergoes reductive elimination
Pyrrolidines from β-Aminoselenides via Radical Cyclization. Diastereoselectivity Control by the N-Substituent
作者:Magnus Besev、Lars Engman
DOI:10.1021/ol005829x
日期:2000.6.1
radicals-were prepared by ring opening of N-allylaziridines with benzeneselenol under acidic conditions or by sodium cyanoborohydride reduction of N-allylimines of alpha-phenylselenenyl ketones. The effect of various N-protective groups (acyl, sulfonyl, or phosphinoyl) on diastereoselectivity in thermally or photochemically initiated 3-aza-5-hexenyl reductive radicalcyclization was studied. Whereas N-unprotected
Rhodium-Catalyzed Stereoselective Formation of <i>Z</i>-Enamines from Allylaziridines
作者:France-Aimée Alphonse、Andrei K. Yudin
DOI:10.1021/ja0632557
日期:2006.9.1
Rhodium (I)-catalyzedisomerization of N-allylaziridines affords isolable Z-enamines in excellent yields and with high stereoselectivity. Cationic [Rh(BINAP)(COD)]OTf and RhH(CO)(PPh3)3 follow the same selectivity toward the Z-isomers. This selectivity is not observed with other N-allylamines which give the thermodynamically more stable E-isomers. These unexpected results suggest a possible deviation