Controllable diastereoselective cyclopropanation. Enantioselective synthesis of vinylcyclopropanes via chiral telluronium ylides.
Novel chiral telluronium salts 1 are designed for asymmetric synthesis of 1,3-disubstituted 2-vinylcyclopropanes. The allylides, generated in situ from the corresponding telluronium salt in the presence of different base, reacted with alpha,beta-unsaturated esters, ketones, and amides to afford cis-2-silylvinyl-trans-3-substituted or trans-2-silylvinyl-trans-3-substituted cyclopropane derivatives with high diastereoselectivity and excellent enantioselectivity in good to high yields. Thus, either one of the two diastereomers could be enantioselectively synthesized at will just by the choice of LiTMP/HMPA or LDA/LiBr. The first examples of catalytic ylide reaction for enantioselective synthesis of 1,3-disubstituted 2-vinylcyclopropanes with high distereoselectivity is also achieved.
Liao
Wei-Wei
WW
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China.
Li
Kai
K
Tang
Yong
Y
D000475:Alkenes / Q000737:chemistry; D003500:Cyclization; D003521:Cyclopropanes / Q000138:chemical synthesis*; D013237:Stereoisomerism; D013691:Tellurium / Q000737:chemistry*; D014753:Vinyl Compounds / Q000138:chemical synthesis*
D000475:Alkenes; D003521:Cyclopropanes; D014753:Vinyl Compounds; D013691:Tellurium