Synthesis of cyclic sulfamoyl carbamates and ureas via ring-closing metathesis

Dougherty, Jack; Jiménez, M.; Hanson, Paul R.

doi:10.1016/j.tet.2005.03.140

Cited by 20 publications

(5 citation statements)

References 55 publications

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“…The unsaturated handle branching off the bridgehead in 28 invited the use of ring closing olefin metathesis (RCM), − even though the number of successful applications to 11-membered carbo- and heterocycles is comparatively small and the yields were rather moderate in many cases. − Since RCM is largely driven by the gain in entropy when a given diene substrate is converted into a cyclic olefin plus ethylene (which desolvates upon evaporation), the reaction does not allow large enthalpic barriers to be overcome. 11-Membered rings, however, largely draw their chemical and physical attributes from transannular as well as angle strain; in the transition state, these factors represent formidable kinetic handicaps for ring closure …”

Section: Resultsmentioning

confidence: 99%

A Unified Approach to Polycyclic Alkaloids of the Ingenamine Estate: Total Syntheses of Keramaphidin B, Ingenamine, and Nominal Njaoamine I

et al. 2021

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Many polycyclic marine alkaloids are thought to derive from partly reduced macrocyclic alkylpyridine derivatives via a transannular Diels–Alder reaction that forms their common etheno-bridged diaza-decaline core (“Baldwin–Whitehead hypothesis”). Rather than trying to emulate this biosynthesis pathway, a route to these natural products following purely chemical logic was pursued. Specifically, a Michael/Michael addition cascade provided rapid access to this conspicuous tricyclic scaffold and allowed different handles to be introduced at the bridgehead quarternary center. This flexibility opened opportunities for the formation of the enveloping medium-sized and macrocyclic rings. Ring closing alkyne metathesis (RCAM) proved most reliable and became a recurrent theme en route to keramaphidin B, ingenamine, xestocyclamine A, and nominal njaoamine I (the structure of which had to be corrected in the aftermath of the synthesis). Best results were obtained with molybdenum alkylidyne catalysts endowed with (tripodal) silanolate ligands, which proved fully operative in the presence of tertiary amines, quinoline, and other Lewis basic sites. RCAM was successfully interlinked with macrolactamization, an intricate hydroboration/protonation/alkyl-Suzuki coupling sequence, or ring closing olefin metathesis (RCM) for the closure of the second lateral ring; the use of RCM for the formation of an 11-membered cycle is particularly noteworthy. Equally rare are RCM reactions that leave a pre-existing triple bond untouched, as the standard ruthenium catalysts are usually indiscriminative vis-à-vis the different π-bonds. Of arguably highest significance, however, is the use of two consecutive or even concurrent RCAM reactions en route to nominal njaoamine I as the arguably most complex of the chosen targets.

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Section: Resultsmentioning

confidence: 99%

A Unified Approach to Polycyclic Alkaloids of the Ingenamine Estate: Total Syntheses of Keramaphidin B, Ingenamine, and Nominal Njaoamine I

et al. 2021

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“…Removal of the Boc group with TFA led to the monoallylated amine 12 , which reacted with allylisocyanate to form the desired diallylurea 16 . Unfortunately, all attempts to form the seven-membered cyclic urea 17 via RCM( 19 ) with Grubb’s second-generation catalysts at room temperature or reflux in either CH 2 Cl 2 or toluene failed and only starting material was recovered.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Conformational Analysis of Locked Carbocyclic Analogues of 1,3-Diazepinone Riboside, a High-Affinity Cytidine Deaminase Inhibitor

et al. 2009

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Cytidine deaminase (CDA) catalyzes the deamination of cytidine via a hydrated transition-state intermediate that results from the nucleophilic attack of zinc-bound water at the active site. Nucleoside analogues where the leaving NH3 group is replaced by a proton and prevent conversion of the transition state to product are very potent inhibitors of the enzyme. However, stable carbocyclic versions of these analogues are less effective as the role of the ribose in facilitating formation of hydrated species is abolished. The discovery that a 1,3-diazepinone riboside (4) operated as a tight-binding inhibitor of CDA independent of hydration provided the opportunity to study novel inhibitors built as conformationally locked, carbocyclic 1,3-diazepinone nucleosides to determine the enzyme’s conformational preference for a specific form of sugar pucker. This work describes the synthesis of two target bicyclo[3.1.0]hexane nucleosides, locked as north (5) and south (6) conformers, as well as a flexible analogue (7) built with a cyclopentane ring. The seven-membered 1,3-diazepinone ring in all the three targets was built from the corresponding benzoyl-protected carbocyclic bis-allyl ureas by ring-closing metathesis. The results demonstrate CDA’s binding preference for a south sugar pucker in agreement with the high-resolution crystal structures of other CDA inhibitors bound at the active site.

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“…To achieve this they used 3-component coupling, Mitsunobu alkylation, and ring-closing metathesis and the secondgeneration Grubbs catalyst. 1124 The synthesis and X-ray crystal structure of the dithiatetrazocine 537 and the permethylated derivative 537 (R = Me) have also been reported. 1125 A general method for synthesis of n-membered cyclic sulfamides has been reported.…”

Section: Inorganic Industrial and Analytical Studiesmentioning

confidence: 99%

“…To achieve this they used 3-component coupling, Mitsunobu alkylation, and ring-closing metathesis and the second-generation Grubbs catalyst …”

Section: Cyclic Sulfamidesmentioning

confidence: 99%

Sulfamic Acid and Its N- and O-Substituted Derivatives

2013

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Synthesis of cyclic sulfamoyl carbamates and ureas via ring-closing metathesis

Cited by 20 publications

References 55 publications

A Unified Approach to Polycyclic Alkaloids of the Ingenamine Estate: Total Syntheses of Keramaphidin B, Ingenamine, and Nominal Njaoamine I

A Unified Approach to Polycyclic Alkaloids of the Ingenamine Estate: Total Syntheses of Keramaphidin B, Ingenamine, and Nominal Njaoamine I

Synthesis and Conformational Analysis of Locked Carbocyclic Analogues of 1,3-Diazepinone Riboside, a High-Affinity Cytidine Deaminase Inhibitor

Sulfamic Acid and Its N- and O-Substituted Derivatives

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