Optisch aktives Dipropylcyclopropan durch enthalogenierende Cyclisierung von optisch aktivem 4,6-Dibromnonan

Optically active trans-dipropylcyclopropane (I) and its optically inactive cis isomer (II) were prepd. from nonane-4,6-dione by redn. with NaBH4, esterification of the di-Li salt with phthalic anhydride, resolution of the stereoisomers with brucine, hydrolysis of the optically active ester, bromination with Ph3PBr2, and cyclization with Li-Hg. [on SciFinder (R)