Synthesis and properties of optically active helical metallocene oligomers
作者:Thomas J. Katz、Anantha Sudhakar、Mark F. Teasley、Adam M. Gilbert、William E. Geiger、Matthew P. Robben、Martin Wuensch、Michael D. Ward
DOI:10.1021/ja00061a018
日期:1993.4
Syntheses are described for optically active oligomers 9 and 27. The steps required have three essential features. (1) A bromine directs a photocyclization, blocking both the position it occupies and the one adjacent. (2) An acid scavenger (propylene oxide) prevents benzylicethers from being eliminated during photocyclization. (3) The stereogenicity of one carbon controls the direction in which the