天然产物葡萄孢酮立体构型的解析

Stereo-chemistry of Natural Product Botrytinone

从海洋来源真菌葡萄孢菌代谢产物中分离得到的天然产物葡萄孢酮结构式中含有3个手性中心,二维NOE谱解析和量子化学计算均证明,7-甲基和5-羟基在同一平面,而4-羟基在另一个平面内。其对溴苯甲酰化衍生物C21H15Br2ClO5的X射线衍射分析证明,晶体属于三斜晶系的P-1空间群,晶胞参数a=0.668 47(5)nm,b=1.218 90(9)nm,c=1.307 8(1)nm,α=83.984(1)°,β=80.366(1)°,γ=84.514(1)°,V=1.041 5(1)nm3和Z=2,进一步确定了葡萄孢酮的相对构型。葡萄孢酮对溴苯甲酰化衍生物C21H15Br2ClO5的圆二色谱(CD)在243 nm(Δε-39.9)出现负的cotton效应,利用CD激子手性法解析了其绝对构型。最终确定了葡萄孢酮结构式为(4R,5S,6R)-4,5-二羟基-3-(1-羟甲基)-2-环戊烯-1-酮。

In the molecule of the natural product botrytinone isolated from the metabolites of marine-derived fungus Botrytis sp. , there are three chiral centers. 2D NOE spectrum and quantum chemistry calculation all confirmed that the 7-CH3 and 5-OH are on the same side and the 4-OH on the other side. On the basis of X-ray diffraction analysis, its p-bromobenzoyl derivative C21H15Br2CIO5 belongs to triclinic system with space groupP-1, a =0.668 47（5） nm, b =1.218 90（9） nm, c=1.307 8（1） nm,α =83.984（1）°, β= 80. 366 （ 1 ） °, γ = 84. 514 （ 1 ） °, V = 1. 041 5 （ 1 ） nm^3, and Z = 2, which further support its relative structure. The CD spectrum of its p-bromobenzoyl derivative shows minor Cotton effection at 243 nm（ △ε -39. 9）. The absolute configuration was elucidated by CD exciton chirality method. Finally it was determined to be （4R, 5S,6R）-4,5-dihydroxy-3-（1-hydroxyethvl） -2-cyclooenten-1-one.