A catalytically asymmetric synthesis of α-(hydroxyalkyl)-tri-n-butylstannanes 1 in good-excellent yields and enantioselectivities (up to 98% e.e.) via addition of ethyl(tri-n-butylstannyl)zinc to aldehydes was achieved. In practice, 1 was isolated after protection as its more stable ester or thiocarbamate (PG). The reagent was prepared from equimolar amounts of tri-n-butylstannyl hydride and Et2Zn in DME so as to avoid contamination by lithium and magnesium ions which suppress enantioselectivity.
Synthesis of Enantioenriched α-(Hydroxyalkyl)-tri-<i>n</i>-butylstannanes
作者:Anyu He、John R. Falck
DOI:10.1002/anie.200802313
日期:2008.8.18
A catalytically asymmetric synthesis of α-(hydroxyalkyl)-tri-n-butylstannanes 1 in good-excellent yields and enantioselectivities (up to 98% e.e.) via addition of ethyl(tri-n-butylstannyl)zinc to aldehydes was achieved. In practice, 1 was isolated after protection as its more stable ester or thiocarbamate (PG). The reagent was prepared from equimolar amounts of tri-n-butylstannyl hydride and Et2Zn in DME so as to avoid contamination by lithium and magnesium ions which suppress enantioselectivity.
Stereospecific Cross-Coupling of α-(Thiocarbamoyl)organostannanes with Alkenyl, Aryl, and Heteroaryl Iodides
作者:J. R. Falck、Paresh K. Patel、Anish Bandyopadhyay
DOI:10.1021/ja064948q
日期:2007.1.1
PTC-protected alpha-hydroxystannanes cross-couple with alkenyl/aryl/heteroaryliodides in moderate to good yields using copper(I) thiophene-2-carboxylate (CuTC) in THF at or below room temperature. Simple aryliodides and 1-iodocyclohexene, two classes of electrophiles that typically react sluggishly, are also good substrates. Cross-couplings proceed with retention of configuration at the alkenyl-