X-ray Crystal Structures of Intermediates of the Stereoselective (±)-Grandisol Synthesis Based on the Remote Alkylation Protocol
作者:Gerimário F. de Sousa、Hugo J. Monteiro、Inês S. Resck、Claudia C. Gatto、Javier Ellena、José R. Sabino
DOI:10.1007/s10870-013-0411-4
日期:2013.5
Starting from easily prepared (cyclobutylsulfonyl)benzene (1), a stereoselective synthesis of (±)-grandisol, accomplished in nine steps, with an overall yield of ca. 18 %, has been presented by Monteiro and Stefani (Eur J Org Chem 14:2659–2663, 2001). Most of the synthetic intermediates were secured in good to excellent yields as crystalline compounds requiring no or minimal purification, should being amenable to scale up. The structures and absolute stereochemistry of (2), (3), (4a), (5), (8) and (9) were established by IR and NMR (1H, 13C) spectroscopies and confirmed by X-ray diffraction analysis. Compound (2) crystallizes in orthorhombic Pbca, a = 16.0565(5), b = 9.5144(6), c = 23.9728(7) Å, the (3) crystallizes in monoclinic P21/c, a = 5.6390(5), b = 17.8630(16), c = 12.8678(12) Å and β = 111.928(7)°, the (4a) crystallizes in monoclinic P21/c, a = 5.7002(9) Å, b = 17.2752(14) Å, c = 14.9168(9) Å and β = 109.464(8)°. The other three cyclobutylsulfonyl derivatives crystallize in the same monoclinic space group P21/c with cell parameters (5) a = 8.072(4), b = 11.486(9), c = 14.565(8) Å and β = 101.373(4)°, (8) a = 11.3448(2), b = 7.9377(1), c = 18.5329(4) Å and β = 94.147(1)° and (9) a = 37.7571(9), b = 11.4434(3), c = 8.1824(2) Å and β = 90.748(1)°. X-ray crystal structures of six synthetic intermediates prepared from the stereoselective synthesis of (±)-grandisol.
从容易制备的(环丁基磺酰基)苯(1)开始,立体选择性合成(±)-grandisol,分九步完成,总产率约为。 18%,由 Monteiro 和 Stefani 提出(Eur J Org Chem 14:2659–2663, 2001)。大多数合成中间体都具有良好到优异的收率,因为结晶化合物不需要或只需最少的纯化,应该适合扩大规模。 (2)、(3)、(4a)、(5)、(8)和(9)的结构和绝对立体化学通过IR和NMR (1H, 13C)光谱确定,并通过X射线衍射分析证实。化合物(2)结晶为斜方Pbca,a = 16.0565(5),b = 9.5144(6),c = 23.9728(7) Å,(3)结晶为单斜P21/c,a = 5.6390(5),b = 17.8630(16), c = 12.8678(12) Å 和 β = 111.928(7)°, (4a) 结晶为单斜晶系 P21/c, a = 5.7002(9) Å, b = 17.2752(14) Å, c = 14.9168(9) Å 和 β = 109.464(8)°。其他三种环丁基磺酰基衍生物结晶在相同的单斜空间群 P21/c 中,晶胞参数为 (5) a = 8.072(4), b = 11.486(9), c = 14.565(8) Å 和 β = 101.373(4)° , (8) a = 11.3448(2), b = 7.9377(1), c = 18.5329(4) Å 和 β = 94.147(1)° 且 (9) a = 37.7571(9), b = 11.4434(3) ,c = 8.1824(2) Å 和 β = 90.748(1)°。由 (±)-grandisol 立体选择性合成制备的六种合成中间体的 X 射线晶体结构。