Addition of cyclopropylphosphonates to aldehydes

Hirao, Toshikazu; Nakamura, Tõru; Hagihara, Masahiko; Agawa, Toshio

doi:10.1021/jo00350a083

Cited by 13 publications

(3 citation statements)

References 3 publications

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“…This material was chromatographed on a silica gel column with a 5% acetone-hexane mixture as the eluent. The first fraction contained 400 mg (30% yield) of a white solid whose structure was assigned as trans-[2,2-dimethyl-1-(phenylthio)-3-(p-tolylsulfonyl)cyclopropyl]trimethylsilane (33) on the basis of the following data: mp 96-97 °C; IR (KBr) 3080, 3000, 2960, 1600, 1590, 1485, 1150, 1090, 850, 745, and 670 cm"1; NMR (90 MHz, CC14) 0.38 (s, 9 ), 1.29 (s, 3 ), 1.58 (s, 3 H), 2.29 (s, 1 H), 2.39 (s, 3 ), 7.39-7.10 (m, 7 H), and 7.65 (d, 2 H, J = 9.0 Hz); 13C NMR (20 UV (95% ethanol) 228 nm (e 20000) and 265 (7700). Anal.…”

Section: Methodsmentioning

confidence: 99%

Chemical reactivity and configurational properties of cyclopropyl carbanions derived from a silyl sulfonyl substituted cyclopropene

Padwa¹,

Wannamaker²,

Dyszlewski³

1987

J. Org. Chem.

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3,3-Dimethyl-l-(p-tolylsulfonyl)-2-(trimethylsilyl)cyclopropene was prepared by the 1,3-dipolar cycloaddition of 2-diazopropane with p-tolyl2-(trimethylsilyl)ethyyl sulfone followed by photoextrusion of nitrogen from the resulting 3H-pyrazole. Treatment of this material with sodium methoxide produced trans-l-methoxy-2-@tolylsulfonyl)-3,3-dimethylcyclopropane. No detectable quantities of the cis isomer were present in the crude reaction mixture. The cyclopropyl carbanion derived from deprotonation of the (methoxysulfony1)-substituted cyclopropane reacts smoothly with a variety of electrophiles to give a single stereoisomer. The observed stereoselectivity can be rationalized in terms of intramolecular chelation of the cyclopropyl lithiate w i t h the neighboring methoxy group. The presence of an electronegative P-sulfonyl group also facilitates cyclopropyl carbanion interconversion. In this case the observed stereoselectivity is probably related to an anomeric effect. The favored cyclopropyl carbanion corresponds to the stereoisomer that permits interaction of the carbanion lone pair with the vacant u* orbital on the adjacent carbon containing the electronegative atom.

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Section: Methodsmentioning

confidence: 99%

Chemical reactivity and configurational properties of cyclopropyl carbanions derived from a silyl sulfonyl substituted cyclopropene

Padwa¹,

Wannamaker²,

Dyszlewski³

1987

J. Org. Chem.

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“…The challenging synthesis of such phosphonates is an important goal as these compounds should be convenient precursors for a-substituted cyclopropylphosphonates Scheme 1. [26] We herein describe several routes for the synthesis of cyclopropylphosphonate 1, two of which were found to be practical and efficient (Table 1).…”

Section: Introductionmentioning

confidence: 99%

Studies of the Synthesis of Diethyl Cyclopropylphosphonate and Its Thio and Seleno Analogs

Zafrani

Chen

Ashkenazi

et al. 2008

Synthetic Communications

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“…Coupling diethylchlorophosphate with 6-methoxy-2-methylbenzothiazole in the presence of lithium diisopropylamide (LDA), that was freshly prepared in one-pot, produced diethyl phosphonate derivative 2 in 67% yield. 34,35 The nitro group of compound 3 was reduced with iron in acidic ethanol to yield amine 4 in 28% yield. Reduction with SnCl 2 in EtOH or acidic MeOH was less effective.…”

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confidence: 99%

Synthesis of a PET tau tracer [11C]PBB3 for imaging of Alzheimer’s disease

Wang

Gao

et al. 2015

Bioorganic & Medicinal Chemistry Letters

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Abstract-The authentic standard PBB3 and its precursor N-desmethyl-PBB3 as well as TBS-protected N-desmethyl-PBB3 precursor for radiolabeling were synthesized from 5-bromo-2-nitropyridine, acrolein diethyl acetal, 6-methoxy-2-methylbenzothiazole, and diethylchlorophosphate with overall chemical yield 1% in six steps, 2% in five steps, and 1% in six steps, respectively. [11 C]PBB3 was prepared from either desmethyl-PBB3 or TBS-protected desmethyl-PBB3 with [11 C]CH 3 OTf through N-[ 11 C]methylation and isolated by HPLC combined with SPE in 20-25% and 15-20% radiochemical yield, respectively, based on [ 11 C]CO 2 and decay corrected to end of bombardment (EOB). The radiochemical purity was >99%, and the specific activity at EOB was 370-1110 GBq/mol with a total synthesis time of ~40-minutes from EOB.

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Addition of cyclopropylphosphonates to aldehydes

Cited by 13 publications

References 3 publications

Chemical reactivity and configurational properties of cyclopropyl carbanions derived from a silyl sulfonyl substituted cyclopropene

Chemical reactivity and configurational properties of cyclopropyl carbanions derived from a silyl sulfonyl substituted cyclopropene

Studies of the Synthesis of Diethyl Cyclopropylphosphonate and Its Thio and Seleno Analogs

Synthesis of a PET tau tracer [11C]PBB3 for imaging of Alzheimer’s disease

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