Binaphthol-titanium-promoted, highly enantiocontrolled, Diels-Alder cycloadditions of electronically matched 2-pyrones and vinyl ethers: Streamlined asymmetric synthesis of an A-ring precursor to physiologically active 1α-hydroxyvitamin D3 steroids
作者:Gary H. Posner、Franck Eydoux、J.K. Lee、D.Scott Bull
DOI:10.1016/s0040-4039(00)78338-9
日期:1994.10
Bicyclic lactones 4, A-ring precursors to diverse physiologically active 1α-hydroxyvitamin D3 analogs, were prepared in excellent yields and enantiomeric purities via chiral, non-racemic Lewis acid-promoted, mild, inverse-electron-demand 4+2-cycloadditions.
双环内酯4是多种生理活性1α-羟基维生素D 3类似物的A环前体,是通过手性,非外消旋路易斯酸促进的,温和的,反电子需求的4 + 2-环加成法制得的,具有优异的收率和对映体纯度。。