Harmjanz M, Gill H S, Scott M J
Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611-7200, USA.
J Org Chem. 2001 Aug 10;66(16):5374-83. doi: 10.1021/jo010163l.
The MacDonald [2 + 2]-type condensation of readily available 5-aryl-substituted dipyrromethanes with acenaphthenequinone leads to the trans-syn- and anti-porphodimethenes, which in turn can be converted to the alpha,alpha- and alpha,beta-porphyrin atropisomers, respectively. Treatment of the metalated or unmetalated porphodimethenes with KOH or NaOMe in THF followed by protonation with HCl results in a ring opening of the acenaphthenone and formation of the trans-8-carboxynaphthylporphyrins or their esters (NaOMe) after oxidation. Alternatively, the porphyrin formation can be accomplished by reaction of the porphodimethenes with acids in the presence of water or methanol. Reaction with NaBH(4) in a THF--methanol mixture yields the corresponding dialcohols in nearly quantitative yields. Sixteen different building blocks were prepared in order to evaluate the generality of this new synthetic approach, with Ar = 2,4,6-Me(3)C(6)H(2); 2,6-Cl(2)C(6)H(3); 2,6-F(2)C(6)H(3); 3,4-tBu(2)C(6)H(3); 3,4,5-(MeO)(3)C(6)H(2); 4-BrC(6)H(4); 4-MeC(6)H(4); and 4-MeOOCC(6)H(4) at the meso positions. The synthesized porphodimethenes and porphyrins have been fully characterized, and the X-ray structure analyses of three representative derivatives are presented.
容易获得的5-芳基取代二吡咯甲烷与苊醌发生麦克唐纳[2 + 2]型缩合反应，生成反式-顺式和反式-卟吩二亚甲基，进而可分别转化为α,α-和α,β-卟啉阻转异构体。在四氢呋喃中用氢氧化钾或甲醇钠处理金属化或未金属化的卟吩二亚甲基，随后用盐酸质子化，会导致苊醌开环，并在氧化后形成反式-8-羧基萘基卟啉或其酯（甲醇钠）。或者，卟啉的形成可以通过卟吩二亚甲基在水或甲醇存在下与酸反应来实现。在四氢呋喃 - 甲醇混合物中与硼氢化钠反应，几乎以定量产率得到相应的二醇。制备了16种不同的结构单元，以评估这种新合成方法的通用性，其中在中位的Ar = 2,4,6-三甲基苯基；2,6-二氯苯基；2,6-二氟苯基；3,4-二叔丁基苯基；3,4,5-三甲氧基苯基；4-溴苯基；4-甲基苯基；和4-甲氧基羰基苯基。已对合成的卟吩二亚甲基和卟啉进行了全面表征，并给出了三种代表性衍生物的X射线结构分析结果。
