Unsaturation of ketones, nitriles and lactams with methyl phenylsulfinate

Resek, James E.; Meyers, A. I.

doi:10.1016/0040-4039(95)01461-p

Cited by 52 publications

(20 citation statements)

References 5 publications

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“…Synthesis of chiral dienes commenced with the preparation of (+)‐( 1R , 5R )‐bicyclo[3.3.1]nona‐3,7‐diene‐2,6‐dione ( 2 )16 by sulfinylation17 of enantiomerically pure 2,6‐dione 1 with methyl phenylsulfinate in the presence of sodium hydride, followed by thermal elimination (Scheme ). Luche reduction18 (NaBH 4 /CeCl 3 ) of the obtained bis(enone) 2 in methanol afforded diol 3 as a mixture of endo,endo ‐ and endo,exo ‐diastereomers in ca.…”

Section: Resultsmentioning

confidence: 99%

4,8‐Disubstituted Bicyclo[3.3.1]nona‐2,6‐dienes as Chiral Ligands for Rh‐Catalyzed Asymmetric 1,4‐Addition Reactions

2015

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C2‐symmetric chiral diene ligands based on 4,8‐endo,endo‐disubstituted bicyclo[3.3.1]nona‐2,6‐diene framework have been designed and synthesized. The rhodium complexes of the dienes, which were obtained in a few straightforward steps from enantiomerically pure bicyclo[3.3.1]nonane‐2,6‐dione, exhibited excellent catalytic activity and high enantioselectivity (up to 96 % ee) in the conjugate addition reaction of arylboronic acids to cyclic enones under mild reaction conditions with high atom efficiency.

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Section: Resultsmentioning

confidence: 99%

4,8‐Disubstituted Bicyclo[3.3.1]nona‐2,6‐dienes as Chiral Ligands for Rh‐Catalyzed Asymmetric 1,4‐Addition Reactions

2015

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“…In this process, alkylation at sulfur with concomitant loss of trimethylsilyl fluoride as well as ethene furnishes the desired unsymmetrical sulfoxide (Scheme 7) [51]. Apart from the aforementioned protocols, a few more non-oxidative protocols are also available for synthesis of sulfoxides [53][54][55][56][57][58][59][60][61]. However, most of them are associated with some limitations such as handling of lachrymatory reagents, expensive starting materials, and drastic reaction conditions.…”

Section: Focus Review Articlementioning

confidence: 99%

A Concise Review on Synthesis of Sulfoxides and Sulfones with Special Reference to Oxidation of Sulfides

Kupwade

2019

J. Chem. Rev.

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A large variety of organosulfur compounds have been shown to having diverse biological effects such as antioxidant effects, anti-inflammatory properties, inhibition of platelet aggregation, reduction of systolic blood pressure, and reduction of cholesterol. Among these, sulfoxides and sulfones show wide and significant applications as commodity chemical in various fields of chemistry. Therefore, synthesis of sulfoxides as well as sulfones has remained a point of attraction for synthetic organic chemists. Among array of methods used to synthesize the sulfoxides or sulfones, oxidation of sulfide is the most convenient way. This review precises chemoselective methods for the synthesis of the sulfoxides as well as sulfones focusing on oxidative protocols. This review will aid researchers to explore and utilise the mentioned protocols for different organic transformations.

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“…The incorporation of a remote chloride within nitrile 6 i does not interfere with the exchange alkylation, despite the potential for intramolecular alkylation or elimination (Table 1, entry 17). Functional-group tolerance is further demonstrated by several in situ exchange alkylations in which iPrMgCl is added to a solution of the sulfinyl nitrile and the electrophile in THF at À78 8C ( Table 1, entries 1-3, 5, and [15][16][17]. A premature reaction of iPrMgCl and the electrophile was not observed in any case.…”

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confidence: 95%

“…Alternatively, the sulfinylnitrile 6 a can be prepared by sulfinylating nitrile 9 with methyl phenylsulfinate. [17] Sequential alkylation and oxidation of phenylthioacetonitrile provides another versatile route to sulfinyl nitriles that is ideal for nonsymmetrical substrates (see the Supporting Information for details). [18] The sulfinyl-metal exchange of 6 a is remarkably facile.…”

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Nitrile Alkylations through Sulfinyl–Metal Exchange

Nath

Fleming

2011

Angew Chem Int Ed

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Nitriles play pivotal roles in a diverse range of pharmaceuticals.[1] The nitrile pharmacophore often engages in key hydrogen bonding, as in the blockbuster drug anastrazole (1), [2] in other cases a covalent attachment occurs, as in the anti-diabetic vildagliptin (2, Scheme 1).[3] Syntheses of many nitrile-containing pharmaceuticals, particularly of those bearing quaternary centers, such as anastrazole [1] and the cyclohexylnitriles levocabastine (3) [4] and cilomilast (4), [5] typically involve multiple alkylations.Most alkylations of nitriles employ alkyllithium or metal amide bases, [6] in these cases, monoalkylation is often complicated by overalkylation. [7] A conceptually appealing solution for multiple controlled alkylations of acetonitrile includes two sequential alkylations of an activated acetonitrile (5!6) with a mild base followed by a functional group/ metal exchange alkylation (6!7!8, Scheme 2). The execution of this strategy would allow three consecutive alkylations, require only one equivalent of strong base, and install quaternary centers, as can be found in numerous nitrilecontaining pharmaceuticals.Metal-exchange reactions [8] usually employ halides, [9] trialkylstannanes, [10] or sulfoxides [11] as transferrable precursors. Recently reported halogen-metal exchange reactions of bromo-, iodo-, [12] and even chloronitriles [13] with organolithium and Grignard reagents allow the selective generation of N-lithiated and C-magnesiated nitriles, respectively. Conceptually, an analogous sulfinyl-metal exchange [14] represents a significant advance by avoiding the aggressive reagents typically required for the synthesis of halonitriles, allowing the performance of two alkylations with mild base, and introducing a greater functional-group tolerance.Access to the symmetrical sulfinylnitrile 6 a was achieved by two complementary alkylations [15] of phenylsulfinylacetonitrile [16] (5 a; Scheme 3, conditions 1 and 2). In each case, 1,5-dibromopentane was used as a prototypical bis-electrophile because the resulting nitrile 6 a contains the core cyclohexylnitrile motif embedded within several nitrile-containing pharmaceuticals (see 3 and 4 in Scheme 1). Heating 5 a and 1,5-dibromopentane with Cs 2 CO 3 to reflux in THF smoothly provides 6 a, whereas the use of NaH in DMF allows the analogous alkylation at ambient temperature. Alternatively, the sulfinylnitrile 6 a can be prepared by sulfinylating nitrile 9 with methyl phenylsulfinate.[17] Sequential alkylation and oxidation of phenylthioacetonitrile provides another versatile route to sulfinyl nitriles that is ideal for nonsymmetrical substrates (see the Supporting Information for details).[18]The sulfinyl-metal exchange of 6 a is remarkably facile. iPrMgCl triggers a rapid exchange that is complete within 5 minutes at À78 8C.[19] In sequential sulfinyl-magnesium exchange alkylations, quaternary centers are efficiently installed by the reaction of the magnesiated nitriles with a diverse range of electrophiles (Table 1). Carbonyl-containing ketone, ester, ...

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Unsaturation of ketones, nitriles and lactams with methyl phenylsulfinate

Cited by 52 publications

References 5 publications

4,8‐Disubstituted Bicyclo[3.3.1]nona‐2,6‐dienes as Chiral Ligands for Rh‐Catalyzed Asymmetric 1,4‐Addition Reactions

4,8‐Disubstituted Bicyclo[3.3.1]nona‐2,6‐dienes as Chiral Ligands for Rh‐Catalyzed Asymmetric 1,4‐Addition Reactions

A Concise Review on Synthesis of Sulfoxides and Sulfones with Special Reference to Oxidation of Sulfides

Nitrile Alkylations through Sulfinyl–Metal Exchange

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