Synthesis of new trialkylsilylmethyloxazinones via intramolecular trapping of β-silyl carbocations by an N-Boc group

Brocherieux-Lanoy, Sylvie; Dhimane, Hamid; Poupon, Jean‐Christophe; Vanucci, Corinne; Lhommet, G.

doi:10.1039/a703902f

Cited by 30 publications

(13 citation statements)

References 13 publications

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“…12) The a-o-glycoside 34 was selectively obtained by glycosidation of a 3:7 mixture of 32/33. 1 3 ) A similar participation of the Boc group has recently been reported by Lhornmer and coworkers [47]. J(OH,l) values (27: 10.3 Hz; 33: 11.2 Hz) are rationalized by postulating a H-bond between HO-C(l) and 0-C(6).…”

Section: ')supporting

confidence: 78%

Synthesis and Some Transformations of 2‐Acetamido‐5‐amino‐3,4,6‐tri‐O‐benzyl‐2,5‐dideoxy‐D‐glucono‐1,5‐lactam

Granier

Vasella

1998

Helvetica Chimica Acta

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~~~ ~The lactam 21 was obtained in an overall yield of 72% from the hydroxy amide 16 by oxidation with the Dess-Martin periodinane, acid-catalysed isomerization of the oxidation products in toluene, whereupon 18/19 precipitated, and reductive dehydroxylation of 18/19 (Et,SiH/BF, . OEt,; Scheme I). The amide 16 was obtained by ammonolysis of the N-acetylglucosamine-derived lactone 15. Depending on the oxidation method, 16 yielded the keto amide 17, the hydroxy lactams 18/19, and the pyrrolidinecarboxamide 20 in widely different proportions. The pyrrolidinecarboxamide 20 was not reduced under the conditions of the reductive dehydroxylation. Hydrogenolysis of the benzyl-protected lactam 21 gave the trihydroxy lactam 22, while reduction with NaBH,/ BF, . OEt, led to the 2-acetamidopiperidine derivative 24 (Scheme 2). Selective (tert-butoxy)carbonylation of the lactam 21 (+ 25) followed by NaBH, reduction and acid-catalysed solvolysis in EtOH led to the a-ethoxycarbamates 28/29. Similarly, (tert-but0xy)carbonylation of 1 (+ 31) followed by reduction to 32/33 and glycosidation yielded the ethoxycarbamate 34. Treatment of the GlcNAc-derived ethyl glycosides 28/29 with Me,SiCN/ BF, OEt, gave the equatorial amino nitrile 30. Under similar conditions, the Glc-derived glycoside 34 led to the iminooxazolidinone 35. In the presence of a larger proportion of Me,SiCN at 5". 34 was transformed into the axial, selectively monodebenzylated amino nitrile 36.

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Section: ')supporting

confidence: 78%

Synthesis and Some Transformations of 2‐Acetamido‐5‐amino‐3,4,6‐tri‐O‐benzyl‐2,5‐dideoxy‐D‐glucono‐1,5‐lactam

Granier

Vasella

1998

Helvetica Chimica Acta

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“…When the Boc carbamate‐derived sulfone 5 was subjected to the Bi(OTf) 3 ⋅4 H 2 O‐catalyzed allylation conditions (Scheme ), the cyclic carbamate 6 was obtained as the major product (36%, dr =82:18), along with the corresponding allylation product 7 , albeit in low yield (16%). Such a cyclic carbamate resulting from the internal capture of an intermediate β‐silyl cation with the Boc group and concomitant loss of isobutylene had already been reported in the literature with tert ‐butoxycarbonylpiperidine derivatives 14…”

Section: Resultsmentioning

confidence: 60%

Bismuth Triflate‐Catalyzed Addition of Allylsilanes to N‐Alkoxycarbonylamino Sulfones: Convenient Access to 3‐Cbz‐Protected Cyclohexenylamines

Ollevier

2009

Adv Synth Catal

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Bismuth triflate was found to be an efficient catalyst in the Sakurai reaction of allyltrimethylsilanes with N-alkoxycarbonylamino sulfones. The reaction proceeded smoothly with a low catalyst loading of BiA C H T U N G T R E N N U N G (OTf) 3 ·4 H 2 O (2-5 mol%) to afford the corresponding protected homoallylic amines in very good yields (up to 96%). A sequential allylation reaction followed by ring-closing metathesis delivers 6-8 membered 3-Cbz-protected cycloalkenylamines.

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“…Such cyclic carbamate resulting from the internal capture of an intermediate b-silyl cation with the Boc group and concomitant loss of isobutylene has already been reported in the literature [59]. 76 T. Ollevier Encouraged by our previous results, we studied the allylation of bifunctional sulfones derived from dialdehydes such as terephthalaldehyde and isophthalaldehyde (Scheme 3).…”

Section: Bismuth Triflate-catalyzed Sakurai Allylation Reactionmentioning

confidence: 80%

Bismuth-Catalyzed Addition of Silyl Nucleophiles to Carbonyl Compounds and Imines

Ollevier

2011

Bismuth-Mediated Organic Reactions

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Bismuth triflate was found to be an efficient catalyst both in the Mannich-type reaction of silyl enolates and in the Sakurai reaction of allyltrimethylsilane with N-alkoxycarbonylamino sulfones. The reactions proceeded smoothly with a low catalyst loading of Bi(OTf)(3)·4H(2)O (0.5-5.0 mol%) to afford the corresponding protected β-amino carbonyl compounds and homoallylic amines in very good yields (up to 96%). The latter compounds could also be obtained via a bismuth-mediated three-component reaction. We have also developed an efficient vinylogous Mukaiyama aldol reaction of 2-(trimethylsilyloxy)furan with various aromatic aldehydes mediated by bismuth triflate in a low catalyst loading (1 mol%). The reaction proceeds rapidly and affords the corresponding 5-[hydroxy(aryl)methyl]furan-2(5H)-ones in high yields with good to very good diastereoselectivities (diastereoisomeric ratios>98:2). Such selectivities, although previously reported with other Lewis acids, could be achieved with a much lower catalyst loading. 5-[Hydroxy(alkyl)methyl]furan-2(5H)-ones derived from ketones could also be obtained with good diastereoselectivities. The vinylogous Mukaiyama aldol reaction has also been extended to 2,2-dimethyl-6-methylene-4-(trimethyl-silyloxy)-1,3-diox-4-ene using 1 mol% of Bi(OTf)(3)·4H(2)O.

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Synthesis of new trialkylsilylmethyloxazinones via intramolecular trapping of β-silyl carbocations by an N-Boc group

Cited by 30 publications

References 13 publications

Synthesis and Some Transformations of 2‐Acetamido‐5‐amino‐3,4,6‐tri‐O‐benzyl‐2,5‐dideoxy‐D‐glucono‐1,5‐lactam

Synthesis and Some Transformations of 2‐Acetamido‐5‐amino‐3,4,6‐tri‐O‐benzyl‐2,5‐dideoxy‐D‐glucono‐1,5‐lactam

Bismuth Triflate‐Catalyzed Addition of Allylsilanes to N‐Alkoxycarbonylamino Sulfones: Convenient Access to 3‐Cbz‐Protected Cyclohexenylamines

Bismuth-Catalyzed Addition of Silyl Nucleophiles to Carbonyl Compounds and Imines

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