Sequential and regioselective Friedel–Crafts reactions of gem-dihalogenocyclopropanecarbonyl chlorides with benzenes for the synthesis of 4-aryl-1-naphthol derivatives
作者:Yoshinori Nishii、Yoo Tanabe
DOI:10.1039/a605030a
日期:——
Novel, sequential and regioselective FriedelâCrafts type
reactions of (E)-3-aryl-2,2-dihalogenocyclopropanecarbonyl
chlorides 1 and 2,2-dichlorocyclopropanecarbonyl chlorides 3 with
benzenes produce various 4-aryl-3-halogeno-1-naphthols 2 and
4-aryl-1-naphthols 4, respectively. One of the benzannulations involves
the intramolecular cyclization of acid chlorides 1, followed by
intermolecular coupling with substituted benzenes to give
4-aryl-3-halogeno-1-naphthols 2. As a demonstration of this annulation,
4-aryl-3-bromo-1-naphthols 2i and 2k are successfully converted into new
analogues of 1-aryl-3-hydroxymethyl-4-methoxy-2-naphthoic acid lactones
13, a class of lignan lactones. The other benzannulation involves three
series of reactions using acid chlorides 3aâc: (1) the
intermolecular FriedelâCrafts acylation of 3 with one benzene
molecule giving the intermediary
2,2-dichlorocyclopropyl(phenyl)methanones 14aâc; (2) the
intermolecular trapping of 14aâc with another benzene molecule
accompanied by regioselective ring opening; and (3) the final
intramolecular cyclization giving 4-phenyl-1-naphthols 4aâc. The
use of p-xylene also gives the corresponding
4-(p-xylyl)-1-naphthol 4d. The reactions of
alternatively prepared ketones 14 with benzenes gives a variety of
âunsymmetricallyâ substituted 4-aryl-1-naphthols
4c,eâk under identical conditions. However, the reaction using
p-methoxyphenyl ketone analogues 14g does not produce
4-aryl-1-naphthols, but gives
5-aryl-2-(p-methoxyphenyl)-3-methylfurans 16. These
annulations proceed straightforwardly (in a one-pot manner) and this
variation is due to the highly regioselective cyclopropane
ring-openings.
新颖的、顺序的以及区域选择性的Friedel-Crafts类反应,通过苯与(E)-3-芳基-2,2-二卤代环丙烷羧酰氯1和2,2-二氯环丙烷羧酰氯3发生反应,生成各种4-芳基-3-卤代-1-萘醇2和4-芳基-1-萘醇4。其中一类苯环增殖反应涉及酸氯1的分子内环化,随后与取代苯的分子间耦合,生成4-芳基-3-卤代-1-萘醇2。作为这一环增殖反应的示范,成功将4-芳基-3-溴-1-萘醇2i和2k转化为新的1-芳基-3-羟甲基-4-甲氧基-2-萘酸内酯类化合物13,这是一类木质素内酯。另一类苯环增殖反应涉及使用酸氯3a-c进行三系列反应:(1)与一个苯分子的分子间Friedel-Crafts酰基化反应,得到中间体2,2-二氯环丙基(苯基)甲酮14a-c;(2)与另一个苯分子的分子间捕捉14a-c,伴随区域选择性的开环;(3)最终的分子内环化反应生成4-苯基-1-萘醇4a-c。使用对二甲苯也能得到相应的4-(对二甲基基)-1-萘醇4d。交替制备的酮14与苯的反应在相同条件下生成多种“不对称”取代的4-芳基-1-萘醇4c,e-k。然而,使用对甲氧基苄基酮类化合物14g的反应并不产生4-芳基-1-萘醇,而是生成5-芳基-2-(对甲氧基苄基)-3-甲基呋喃16。这些环增殖反应在单锅条件下直接进行,这种变化是由于高度区域选择性的环丙烷开环反应造成的。