William D. Wulff

article

Catalytic Asymmetric Epoxidation of Aldehydes with Two VANOL‐Derived Chiral Borate Catalysts

Anil K. Gupta, Xiaopeng Yin, Munmun Mukherjee, Aman A. Desai, more

Angewandte Chemie International Edition > 58 > 11 > 3361 - 3367

A highly diastereo‐ and enantioselective method for the epoxidation of aldehydes with α‐diazoacetamides has been developed with two different borate ester catalysts of VANOL. Both catalytic systems are general for aromatic, aliphatic, and acetylenic aldehydes, giving high yields and inductions for nearly all cases. One borate ester catalyst has two molecules of VANOL and the other only one VANOL....

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Catalytic Asymmetric Epoxidation of Aldehydes with Two VANOL‐Derived Chiral Borate Catalysts

Anil K. Gupta, Xiaopeng Yin, Munmun Mukherjee, Aman A. Desai, more

Angewandte Chemie > 131 > 11 > 3399 - 3405

A highly diastereo‐ and enantioselective method for the epoxidation of aldehydes with α‐diazoacetamides has been developed with two different borate ester catalysts of VANOL. Both catalytic systems are general for aromatic, aliphatic, and acetylenic aldehydes, giving high yields and inductions for nearly all cases. One borate ester catalyst has two molecules of VANOL and the other only one VANOL....

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Enantioselective Palladium‐Catalyzed Carbonylative Carbocyclization of Enallenes via Cross‐Dehydrogenative Coupling with Terminal Alkynes: Efficient Construction of α‐Chirality of Ketones

Bin Yang, Youai Qiu, Tuo Jiang, William D. Wulff, more

Angewandte Chemie International Edition > 56 > 16 > 4535 - 4539

An enantioselective Pd^II/Brønsted acid‐catalyzed carbonylative carbocyclization of enallenes ending with a cross‐dehydrogenative coupling (CDC) with a terminal alkyne was developed. VAPOL phosphoric acid was found as the best co‐catalyst among the examined 28 chiral acids, for inducing the enantioselectivity of α‐chiral ketones. As a result, a number of chiral cyclopentenones were easily synthesized...

article

Enantioselective Palladium‐Catalyzed Carbonylative Carbocyclization of Enallenes via Cross‐Dehydrogenative Coupling with Terminal Alkynes: Efficient Construction of α‐Chirality of Ketones

Bin Yang, Youai Qiu, Tuo Jiang, William D. Wulff, more

Angewandte Chemie > 129 > 16 > 4606 - 4610

An enantioselective Pd^II/Brønsted acid‐catalyzed carbonylative carbocyclization of enallenes ending with a cross‐dehydrogenative coupling (CDC) with a terminal alkyne was developed. VAPOL phosphoric acid was found as the best co‐catalyst among the examined 28 chiral acids, for inducing the enantioselectivity of α‐chiral ketones. As a result, a number of chiral cyclopentenones were easily synthesized...

article

Catalyst‐Controlled Multicomponent Aziridination of Chiral Aldehydes

Munmun Mukherjee, Yubai Zhou, Yijing Dai, AniL K. Gupta, more

Chemistry – A European Journal > 23 > 11 > 2552 - 2556

A highly diastereoselective and enantioselective method for the multicomponent aziridination of chiral aldehydes has been developed with BOROX catalysts of the VANOL (3,3′‐diphenyl‐2,2′‐bi‐1‐naphthol) and VAPOL (2,2′‐diphenyl‐(4‐biphenanthrol)) ligands. Very high to perfect catalyst control is observed with most all substrates examined including aldehydes with chiral centers in the α‐ and β‐positions...

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Self-assembly of a library of polyborate chiral anions for asymmetric catalytic quinoline reduction

Aman A. Desai, Yong Guan, Aaron L. Odom, Supriyo Majumder, more

Tetrahedron Letters > 2015 > 56 > 23 > 3481-3485

The ‘template’ polyborate BOROX catalysts are shown to mediate the asymmetric transfer hydrogenation of 2-quinolines. The rapid and simple generation of a large family of BOROX catalysts with significantly altered asymmetric pockets is described. A transition state model that explains the enantioselectivity is proposed.

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Catalytic Asymmetric Synthesis of Alkynyl Aziridines: Both Enantiomers of cis‐Aziridines from One Enantiomer of the Catalyst

Yong Guan, Maria P. López‐Alberca, Zhenjie Lu, Yu Zhang, more

Chemistry – A European Journal > 20 > 43 > 13894 - 13900

Alkynyl aziridines can be obtained from the catalytic asymmetric aziridination (AZ reaction) of alkynyl imines with diazo compounds in high yields and high asymmetric inductions mediated by a chiral boroxinate or BOROX catalyst. In contrast to the AZ reaction with aryl‐ and alkyl‐substituted imines, alkynyl imines react to give cis‐substituted aziridines with both diazo esters and diazo acetamides...

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Enantioselective Biomimetic Total Syntheses of Kuwanons I and J and Brosimones A and B

Jianguang Han, Xia Li, Yong Guan, Wenjun Zhao, more

Angewandte Chemie > 126 > 35 > 9411 - 9415

The first enantioselective total syntheses of prenylflavonoid Diels–Alder natural products (−)‐kuwanon I, (+)‐kuwanon J, (−)‐brosimone A, and (−)‐brosimone B have been accomplished from a common intermediate based on a concise synthetic strategy. Key elements of the synthesis include a biosynthesis‐inspired asymmetric Diels–Alder cycloaddition mediated by a chiral ligand/boron Lewis acid, as well...

article

Enantioselective Biomimetic Total Syntheses of Kuwanons I and J and Brosimones A and B

Jianguang Han, Xia Li, Yong Guan, Wenjun Zhao, more

Angewandte Chemie International Edition > 53 > 35 > 9257 - 9261

The first enantioselective total syntheses of prenylflavonoid Diels–Alder natural products (−)‐kuwanon I, (+)‐kuwanon J, (−)‐brosimone A, and (−)‐brosimone B have been accomplished from a common intermediate based on a concise synthetic strategy. Key elements of the synthesis include a biosynthesis‐inspired asymmetric Diels–Alder cycloaddition mediated by a chiral ligand/boron Lewis acid, as well...

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Three‐Component Asymmetric Catalytic Ugi Reaction—Concinnity from Diversity by Substrate‐Mediated Catalyst Assembly

Wenjun Zhao, Li Huang, Yong Guan, William D. Wulff

Angewandte Chemie > 126 > 13 > 3504 - 3509

The first chiral catalyst for the three‐component Ugi reaction was identified as a result of a screen of a large set of different BOROX catalysts. The BOROX catalysts were assembled in situ from a chiral biaryl ligand, an amine, water, BH₃⋅SMe₂ , and an alcohol or phenol. The catalyst screen included 13 different ligands, 12 amines, and 47 alcohols or phenols. The optimal catalyst system (LAP 8‐5‐47)...

article

Three‐Component Asymmetric Catalytic Ugi Reaction—Concinnity from Diversity by Substrate‐Mediated Catalyst Assembly

Wenjun Zhao, Li Huang, Yong Guan, William D. Wulff

Angewandte Chemie International Edition > 53 > 13 > 3436 - 3441

The first chiral catalyst for the three‐component Ugi reaction was identified as a result of a screen of a large set of different BOROX catalysts. The BOROX catalysts were assembled in situ from a chiral biaryl ligand, an amine, water, BH₃⋅SMe₂ , and an alcohol or phenol. The catalyst screen included 13 different ligands, 12 amines, and 47 alcohols or phenols. The optimal catalyst system (LAP 8‐5‐47)...

article

A General Synthesis of Sphinganines through Multicomponent Catalytic Asymmetric Aziridination

Munmun Mukherjee, Yubai Zhou, Anil K. Gupta, Yong Guan, more

European Journal of Organic Chemistry > 2014 > 7 > 1386 - 1390

A catalytic asymmetric synthesis of all four stereoisomers of sphinganine is described starting from hexadecanal. Utilizing either the (R) or (S) enantiomer of a BOROX catalyst, a multicomponent reaction of this aldehyde with an amine and ethyl diazoacetate gives rise to enantiomeric aziridine‐2‐carboxylates. Access to all diastereomers of sphinganine is realized upon ring opening of the enantiopure...

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Vaulted Biaryls in Catalysis: A Structure–Activity Relationship Guided Tour of the Immanent Domain of the VANOL Ligand

Yong Guan, Zhensheng Ding, William D. Wulff

Chemistry – A European Journal > 19 > 46 > 15565 - 15571

The active site in the BOROX catalyst is a chiral polyborate anion (boroxinate) that is assembled in situ from three equivalents of B(OPh)₃ and one of the VANOL ligand by a molecule of substrate. The substrates are bound to the boroxinate by H bonds to oxygen atoms O1–O3. The effects of introducing substituents at each position of the naphthalene core of the VANOL ligand are systematically investigated...

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Synthesis of [m.n]Cyclophanes: Regiochemistry Transfer from Vinyl Halides to Cyclophanes via Fischer Carbene Complexes

Huan Wang, Alexander V. Predeus, William D. Wulff

Chemistry – A European Journal > 19 > 25 > 8261 - 8267

The double benzannulation of bis‐carbene complexes of chromium with α,ω‐diynes generates [m.n]cyclophanes in which all three rings are generated in a single reaction. This triple annulation process is very flexible allowing for the construction of symmetrical [n.n]cyclophanes and unsymmetrical [m.n]cyclophanes as well as isomers in which the two benzene rings are both meta bridged or both para bridged,...

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Rational Synthesis for All All‐Homocalixarenes

Alexander V. Predeus, Vijay Gopalsamuthiram, Richard J. Staples, William D. Wulff

Angewandte Chemie > 125 > 3 > 945 - 949

Alle Größen im Angebot: Die Synthese von Homocalixarenen aller Größen gelang über einen dreifachen Ringschluss von Bis(carbenkomplexen) mit Diinen (siehe Schema). Diese Strategie sollte prinzipiell einen Zugang zu allen Homocalixarenen eröffnen. Wie universell der Ansatz ist, wird durch die Synthese eines pyrrolhaltigen Calixarens demonstriert.

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Rational Synthesis for All All‐Homocalixarenes

Alexander V. Predeus, Vijay Gopalsamuthiram, Richard J. Staples, William D. Wulff

Angewandte Chemie International Edition > 52 > 3 > 911 - 915

Have it all: The synthesis of homocalixarenes of all sizes has been demonstrated using the triple annulation of bis(carbene) complexes with diynes (see scheme). This strategy in principle should allow access to all homocalixarenes. The generality of the synthetic approach is also demonstrated by the preparation of a pyrrole‐containing calixarene.

article

Double Stereodifferentiation in the Catalytic Asymmetric Aziridination of Imines Prepared from α‐Chiral Amines

Li Huang, Yu Zhang, Richard J. Staples, Rui H. Huang, more

Chemistry – A European Journal > 18 > 17 > 5302 - 5313

The catalytic asymmetric aziridination of imines and diazo compounds (AZ reaction) mediated by boroxinate catalysts derived from the VANOL and VAPOL ligands was investigated with chiral imines derived from five different chiral, disubstituted, methyl amines. The strongest matched and mismatched reactions with the two enantiomers of the catalyst were noted with disubstituted methyl amines that had...

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Multicomponent Catalytic Asymmetric Aziridination of Aldehydes

Anil K. Gupta, Munmun Mukherjee, William D. Wulff

Organic Letters > 2011 > 13 > 21 > 5866 - 5869

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Scalable Syntheses of the Vaulted Biaryl Ligands VAPOL and VANOL via the Cycloaddition/Electrocyclization Cascade

Zhensheng Ding, Wynter E. G. Osminski, Hong Ren, William D. Wulff

Organic Process Research & Development > 2011 > 15 > 5 > 1089 - 1107

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Practical Gram Scale Asymmetric Catalysis with Boroxinate Brønsted Acids Derived from the VAPOL and VANOL Ligands

Aman A. Desai, Hong Ren, Munmun Mukherjee, William D. Wulff

Organic Process Research & Development > 2011 > 15 > 5 > 1108 - 1115

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Search results for: William D. Wulff

Catalytic Asymmetric Epoxidation of Aldehydes with Two VANOL‐Derived Chiral Borate Catalysts

Catalytic Asymmetric Epoxidation of Aldehydes with Two VANOL‐Derived Chiral Borate Catalysts

Enantioselective Palladium‐Catalyzed Carbonylative Carbocyclization of Enallenes via Cross‐Dehydrogenative Coupling with Terminal Alkynes: Efficient Construction of α‐Chirality of Ketones

Enantioselective Palladium‐Catalyzed Carbonylative Carbocyclization of Enallenes via Cross‐Dehydrogenative Coupling with Terminal Alkynes: Efficient Construction of α‐Chirality of Ketones

Catalyst‐Controlled Multicomponent Aziridination of Chiral Aldehydes

Self-assembly of a library of polyborate chiral anions for asymmetric catalytic quinoline reduction

Catalytic Asymmetric Synthesis of Alkynyl Aziridines: Both Enantiomers of cis‐Aziridines from One Enantiomer of the Catalyst

Enantioselective Biomimetic Total Syntheses of Kuwanons I and J and Brosimones A and B

Enantioselective Biomimetic Total Syntheses of Kuwanons I and J and Brosimones A and B

Three‐Component Asymmetric Catalytic Ugi Reaction—Concinnity from Diversity by Substrate‐Mediated Catalyst Assembly

Three‐Component Asymmetric Catalytic Ugi Reaction—Concinnity from Diversity by Substrate‐Mediated Catalyst Assembly

A General Synthesis of Sphinganines through Multicomponent Catalytic Asymmetric Aziridination

Vaulted Biaryls in Catalysis: A Structure–Activity Relationship Guided Tour of the Immanent Domain of the VANOL Ligand

Synthesis of [m.n]Cyclophanes: Regiochemistry Transfer from Vinyl Halides to Cyclophanes via Fischer Carbene Complexes

Rational Synthesis for All All‐Homocalixarenes

Rational Synthesis for All All‐Homocalixarenes

Double Stereodifferentiation in the Catalytic Asymmetric Aziridination of Imines Prepared from α‐Chiral Amines

Multicomponent Catalytic Asymmetric Aziridination of Aldehydes

Scalable Syntheses of the Vaulted Biaryl Ligands VAPOL and VANOL via the Cycloaddition/Electrocyclization Cascade

Practical Gram Scale Asymmetric Catalysis with Boroxinate Brønsted Acids Derived from the VAPOL and VANOL Ligands

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