Asymmetric Michael addition using N-cinnamoyl- and N-crotonyl-trans-hexahydrobenzoxazolidin-2-ones
摘要:
Preparation of N-cinnamoyl- and N-crotonyl-oxazolidin-2-ones 2 and 3 or ent-2 and ent-3 from (4S,5s)- and (4R,5R)trans-hexahydrobenzoxazolidin-2-ones 1 or ent-1 are reported. Stereoselective copper promoted conjugated additions of Grignard reagents to chiral N-enoyl amides 2 and 3 or ent-2 and ent-3 in the presence of Zn(II) salts afforded the 1,4-addition products 4-11 and the corresponding enantiomers. (c) 2005 Elsevier Ltd. All rights reserved.
Asymmetric Michael addition using N-cinnamoyl- and N-crotonyl-trans-hexahydrobenzoxazolidin-2-ones
摘要:
Preparation of N-cinnamoyl- and N-crotonyl-oxazolidin-2-ones 2 and 3 or ent-2 and ent-3 from (4S,5s)- and (4R,5R)trans-hexahydrobenzoxazolidin-2-ones 1 or ent-1 are reported. Stereoselective copper promoted conjugated additions of Grignard reagents to chiral N-enoyl amides 2 and 3 or ent-2 and ent-3 in the presence of Zn(II) salts afforded the 1,4-addition products 4-11 and the corresponding enantiomers. (c) 2005 Elsevier Ltd. All rights reserved.