Marshall James A, Eidam Patrick
Department of Chemistry, University of Virginia, PO Box 400319, Charlottesville, Virginia 22904, USA.
Org Lett. 2004 Feb 5;6(3):445-8. doi: 10.1021/ol0363568.
[reaction: see text] Additions of vinylic zinc bromide reagents to alpha-chiral aldehydes (R(1) = CH(2)OTBS, R(2) = Me; R(1) = Me, R(2) = OTBS) in the presence of lithiated (+)- or (-)-N-methylephedrine proceed with predominant reagent control to afford anti or syn adducts stereoselectively, except when the aldehydes possess an alkoxy substituent at the alpha- or beta-positions (R(1) = Me, R(2) = OBn; R(1) = CH(2)OBn, R(2) = Me), in which case chelation-controlled adducts predominate.
[反应：见正文] 在锂化的（+）-或（-）-N-甲基麻黄碱存在下，将乙烯基溴化锌试剂加成到α-手性醛（R(1) = CH(2)OTBS，R(2) = Me；R(1) = Me，R(2) = OTBS）上，主要受试剂控制，立体选择性地得到反式或顺式加合物，除非醛在α-或β-位具有烷氧基取代基（R(1) = Me，R(2) = OBn；R(1) = CH(2)OBn，R(2) = Me），在这种情况下，螯合控制的加合物占主导。
