The reaction of crotyltrialkylstannanes (1) with aldehydes in the presence of BF3,OEt2, produces the corresponding erythro homoallyl alcohols (2) predominantly regardless of the geometry of the double bond. Further, the Lewis acid mediated reaction exhibits the enhanced Cram selectivity in comparison with other allylic organometallic reactions which proceed in the absence of Lewis acids. Use of AlCl3-i-PrOH
Concerning reversal of diastereoselectivity in the BF3 promoted addition of crotyl—organometallic compounds to aldehydes
作者:Yoshinori Yamamoto、Kazuhiro Maruyama
DOI:10.1016/0022-328x(85)80039-5
日期:1985.4
The addition of a mixture of benzaldehyde and BF3·OEt2 to crotyl-organometallic reagents C4H7MLn (1) (M = Cu, Cd, Hg, Tl, Ti, Zr and V) produces predominantly the erythro homoallyl alcohol as well as the α-adduct, while without BF3·OEt2 the threo isomer is formed preferentially.
Erythro-selective addition of crotyltrialkyltins to aldehydes regardless of the geometry of the crotyl unit. Stereoselection independent of the stereochemistry of precursors
Highly Diastereo- and Enantioselective Reagents for Aldehyde Crotylation
作者:Blaine M. Hackman、Pamela J. Lombardi、James L. Leighton
DOI:10.1021/ol0480731
日期:2004.11.1
Two new, crystalline solid, storable, and highly enantioselective reagents for aldehyde crotylation have been developed. Both (cis and trans) crotylsilane reagents are easily prepared in bulk, require trivial reaction conditions, and provide the homoallylic alcohol products with near diastereo- and enantiospecificity in many cases.