Facile Access to Versatile Polyaromatic Building Blocks: Selectively Protected Benzocyclobutenedione Derivatives via Regioselective [2+2] Cycloaddition of -Alkoxybenzyne and Ketene Silyl Acetal

Hamura, Toshiyuki; Hosoya, Takamitsu; Yamaguchi, Hiroki; Kuriyama, Y.; Tanabe, Mitsujiro; Miyamoto, Makoto; Yasui, Yoshizumi; Matsumoto, Takashi; Suzuki, Keisuke

doi:10.1002/1522-2675(200211)85:11<3589::aid-hlca3589>3.0.co;2-z

Cited by 69 publications

(44 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…18,19,26,27 In our strategy, reactions of thiols 6a-f containing linear (entries 1 and 2), branched (entries 3, 4, and 6), and cyclic (entry 5) aliphatic structures, however, successfully generated the corresponding products 8a-f. The primary aliphatic thiols 6a-c gave phthalides 8a-c in less than 5 h. As expected, the steric hindrance of the secondary and tertiary thiols 6d-f affected unfavorably the formation of products 8d-f, which displayed slow reaction rates of 12, 13, and 48 h, respectively.…”

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

“…23,24 Although the functionalized phthalides 3a-c are the most commonly used precursors in Hauser-Kraus annulations, there are only a few reports of synthetic modifications of these compounds. 18,19,25,26 In the present study, a new synthetic strategy is proposed for efficient formation of phthalides 3a and 3c. In this strategy, the advantage of using multi-step reactions of combined reversible-and irreversible processes in a single operation have been explored.…”

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

“…However, there have been only a few attempts made to modify the sulfur moiety in the 3-thiophthalide building blocks. 18,26,27 To overcome these limitations, a new series of 3-thiophthalides were prepared successfully using a large range of different thiols. Furthermore, 3-cyanophthalide 3c, one of the most frequently used donors in the Hauser-Kraus annulation, has also been prepared using the same synthetic concept.…”

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

See 2 more Smart Citations

Tandem reversible addition–intramolecular lactonization for the synthesis of 3-functionalized phthalides

Sakulsombat

Angelin

Ramström

2010

Tetrahedron Letters

View full text Add to dashboard Cite

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

See 1 more Smart Citation

Tandem reversible addition–intramolecular lactonization for the synthesis of 3-functionalized phthalides

Sakulsombat

Angelin

Ramström

2010

Tetrahedron Letters

View full text Add to dashboard Cite

“…2,3 The electrophilic activation of the pyridine ring as in B would trigger ring expansion to produce the requisite azaspiro system C (eq 1).…”

mentioning

confidence: 99%

Ring Expansion Approach to Azaspiro[4.5]decane Skeletons via Electrophilic Activation of Benzocyclobutenols Bearing Pyridyl Group

Hayashi¹,

Ohmori²,

Suzuki³

2011

Chemistry Letters

Self Cite

View full text Add to dashboard Cite

show abstract

“…Commercially available resorcinols 1 were easily converted to 2-iodo-3-triflyloxyphenols 2 according to Suzuki's three-step protocol. 7,8 Dehydrative etherification of 2 with separately prepared azido-substituted alcohols 3 proceeded efficiently upon treatment with triphenylphosphine and diethyl azodicarboxylate to afford the corresponding aryne precursors 4a4g without damaging the azido group stemmed from iminophosphorane formation.…”

Section: Abstract: Aryne | Azide | Benzotriazolementioning

confidence: 99%

Synthesis of Diverse Benzotriazoles from Aryne Precursors Bearing an Azido Group via Inter- and Intramolecular Cycloadditions

2016

Self Cite

View full text Add to dashboard Cite

A diverse range of benzotriazoles were synthesized from various 3-(azidoalkoxy)aryne precursors, which were easily prepared by Mitsunobu etherification. Various bis-1,2,3-triazoles containing a benzotriazole skeleton were obtained via sequential azidealkyne and azidearyne cycloadditions. Intramolecular azidoaryne cycloaddition, conducted using the same starting materials, afforded new types of ring-fused benzotriazoles. In the latter case, the reaction proceeded efficiently even though the regioorientation of the azido group was the reverse of that usually observed in intermolecular reactions between 3-alkoxyarynes and an azide.Benzotriazole is a heterocyclic compound that often forms part of the core skeleton of bioactive compounds, including clinical drugs and drug candidates.1 To address the increasing demand for chemical libraries that facilitate efficient drug discovery, we have constructed a chemical library comprising benzotriazoles bearing various pharmacophores.2 Since benzotriazoles are easily prepared by cycloaddition reactions between arynes and azides, 3 arynes bearing a latently transformable group serve as useful intermediates for preparing a diverse range of benzotriazoles. 2,4,5 In this context, we recently reported a modular synthetic method for the preparation of diverse bis-and tris-1,2,3-triazoles, including the benzotriazole skeleton.2b This approach was based on the use of aryne precursors pro-A bearing a clickable terminal alkyne moiety ( Figure 1A). Various bis-1,2,3-triazoles B were prepared from pro-A via sequential azidearyne and azidealkyne cycloadditions. Herein, we show that the azido-functionalized 3-alkoxyaryne precursors pro-C also serve as useful common platform molecules for the synthesis of diverse benzotriazoles such as bistriazoles D and new types of ring-fused benzotriazoles E, which were obtained via sequential intermolecular cycloadditions and an intramolecular cycloaddition, respectively ( Figure 1B).Various 3-(azidoalkoxy)aryne precursors, the starting materials used in this study, were easily prepared in a convergent manner using the Mitsunobu reaction 6 (Scheme 1). Commercially available resorcinols 1 were easily converted to 2-iodo-3-triflyloxyphenols 2 according to Suzuki's three-step protocol.7,8 Dehydrative etherification of 2 with separately prepared azido-substituted alcohols 3 proceeded efficiently upon treatment with triphenylphosphine and diethyl azodicarboxylate to afford the corresponding aryne precursors 4a4g without damaging the azido group stemmed from iminophosphorane formation. 8The modular synthesis of benzotriazole-containing bis-1,2,3-triazoles was accomplished via sequential cycloadditions to the aryne precursors 4: a copper(I)-catalyzed azidealkyne cycloaddition (CuAAC), 9 followed by silylmethyl Grignard-triggered 2b,2c,5v regioselective azidearyne cycloaddition (Figure 2). This method enabled the facile synthesis of bistriazoles such as 8a8c bearing various functional groups, including silyl, ester, bromo, and pyridyl moieties, in moderate to h...

show abstract

Facile Access to Versatile Polyaromatic Building Blocks: Selectively Protected Benzocyclobutenedione Derivatives via Regioselective [2+2] Cycloaddition of -Alkoxybenzyne and Ketene Silyl Acetal

Cited by 69 publications

References 10 publications

Tandem reversible addition–intramolecular lactonization for the synthesis of 3-functionalized phthalides

Tandem reversible addition–intramolecular lactonization for the synthesis of 3-functionalized phthalides

Ring Expansion Approach to Azaspiro[4.5]decane Skeletons via Electrophilic Activation of Benzocyclobutenols Bearing Pyridyl Group

Synthesis of Diverse Benzotriazoles from Aryne Precursors Bearing an Azido Group via Inter- and Intramolecular Cycloadditions

Contact Info

Product

Resources

About