Synthesis of Propionate Motifs: Diastereoselective Tandem Reactions Involving Anionic and Free Radical Based Processes
详细信息 查看全文
- 作者：Yvan Guindon ; Karine Houde ; Michel Pré ; vost ; Benoit Cardinal-David ; Serge R. Landry ; Benoit Daoust ; Mohammed Bencheqroun ; and Brigitte Gué ; rin
- 刊名：Journal of the American Chemical Society
- 出版年：2001
- 出版时间：September 5, 2001
- 年：2001
- 卷：123
- 期：35
- 页码：8496 - 8501
- 全文大小：112K
- 年卷期：v.123,no.35(September 5, 2001)
- ISSN：1520-5126
文摘
Reported herein is a strategy employing a Mukaiyama reaction in tandem with a hydrogen transferreaction for the elaboration of propionate motifs. The nature of the protecting groups on the chiral 
-alkoxyaldehyde and the type of Lewis acid used are varied to modulate the stereochemical outcome of the tandemreactions. The mode of complexation is thus controlled (monodentate or chelate) for the Mukaiyama reactionto give access to either syn or anti aldol products, precursors of the free radical reduction reaction. The endocycliceffect is subsequently capitalized upon to control the hydrogen transfer step so that the syn-reduced productmay be achieved. Proceeding with excellent yield and diastereoselectivity, the synthetic sequence proposedgives access to syn-syn and syn-anti propionate motifs. Also considered is a complementary approach usinga chelation-controlled Mukaiyama reaction in tandem with a free radical allylation reaction under the controlof the endocyclic effect that leads to the anti-anti product.
-alkoxyaldehyde and the type of Lewis acid used are varied to modulate the stereochemical outcome of the tandemreactions. The mode of complexation is thus controlled (monodentate or chelate) for the Mukaiyama reactionto give access to either syn or anti aldol products, precursors of the free radical reduction reaction. The endocycliceffect is subsequently capitalized upon to control the hydrogen transfer step so that the syn-reduced productmay be achieved. Proceeding with excellent yield and diastereoselectivity, the synthetic sequence proposedgives access to syn-syn and syn-anti propionate motifs. Also considered is a complementary approach usinga chelation-controlled Mukaiyama reaction in tandem with a free radical allylation reaction under the controlof the endocyclic effect that leads to the anti-anti product.