Synthesis, Crystal Structure, and Circular Dichroism Spectra of (1S)-4,8-Diphenylbarbaralane-2,6-dicarbonitrile – Chiroptical Properties of the Transition State of a Degenerate Cope Rearrangement
作者:Helmut Quast、Maximilian Seefelder、Eva-Maria Peters、Karl Peters
DOI:10.1002/(sici)1099-0690(199908)1999:8<1811::aid-ejoc1811>3.0.co;2-v
日期:1999.8
the title compound (1S)-1. Hydroxy ketone rac-endo-4 adopts similar conformations in the solid state and in solution as shown by a comparison of vicinal 1H,1H coupling constants from proton spectra with those calculated from torsional angles in the crystal. The molecular structures of (1S)-1 and (1S)-3 closely resemble those of the corresponding racemates investigated previously. These results show (i)
Diphenylbicyclo [3.3.1]壬烷-2,6-二酮的外消旋- 3在57%的总收率由非对映体的色谱分离(解决- [R - )ñ(1-苯乙基)氨基甲酸酯- 9其由(得到[R )- (1-苯基乙基)异氰酸酯(8)和6-羟基二苯基双环[3.3.1] nonan-2-ones内-和exo - 4。对映体(1 R)-(er = 98:2)和(1 S)-3(er = 97:3)通过从氢化铝锂还原而来的9进行再生,然后对所得二醇进行Swern氧化5。从(1S)-3分三步合成标题化合物(1 S)-1,该方法的收率提高了导致rac - 1的路线。通过氨基甲酸酯内-(1 R)-9和外-(1 S)-9的X射线衍射分析确定绝对构型。还对樟脑酸酯(1 R)-7,中间体rac - endo - 4和(1 S)-进行X射线衍射分析。3,和标题化合物(1 S)-1。羟基酮rac - endo - 4在固态和溶