Allyl Cyanate‐To‐Isocyanate Rearrangement: Preparation of
            <i>tert</i>
            ‐Butyl 3,7‐Dimethylocta‐1,6‐dien‐3‐ylcarbamate

Ichikawa, Yoshiyasu; Kariya, Noriko; Hasegawa, Tomoyuki

doi:10.1002/0471264229.os090.26

Cited by 3 publications

(3 citation statements)

References 40 publications

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“…Hydrogen-bonding and/or π-stacking interactions between the benzamide residue of substrate 13 and the activated form of 6-methylsalicylic acid may be responsible. Treatment of compound 14 with 2,2,2-trichloroacetyl isocyanate in dichloromethane led, after treatment with methanol and silica gel then aqueous workup, to carbamate 15 (88%).…”

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confidence: 99%

A Total Synthesis of the Antifungal Deoxyaminocyclitol Nabscessin B from l-(+)-Tartaric Acid

Yan

Banwell

et al. 2017

Org. Lett.

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Aminocyclitol 2, a recently isolated and notable antifungal agent, was prepared from homochiral γ-hydroxycyclohexenone 4, which is itself available in six steps from l-(+)-tartaric acid (3). The well-defined rigidifying effect arising from the 1,2-diacetal protecting group associated with compound 4 and its derivatives allows for high levels of regio- and stereo-chemical control in the manipulation of the cyclitol framework.

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confidence: 99%

A Total Synthesis of the Antifungal Deoxyaminocyclitol Nabscessin B from l-(+)-Tartaric Acid

Yan

Banwell

et al. 2017

Org. Lett.

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“…Isocyanates 19 reacted further in an MoO 2 Cl 2 (DMF) 2 ‐catalyzed reaction with t BuOH to give carbamates 20 . The use of t BuOLi instead of the Mo catalyst in the second step of the synthesis of carbamate 20a and/or PPh 3 , CBr 4 , and Et 3 N, for the generation of cyanate 18a resulted in almost the same chirality transfer, but somewhat lower yields. Carbamates 19 were hydrolyzed under basic conditions to give the free amines in excellent yields, with very good chirality transfer.…”

Section: Resultsmentioning

confidence: 99%

Rearrangement Reactions Leading to Optically Active α,α‐Disubstituted Primary Allylamines

2017

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Synthetic routes to α,α‐disubstituted allylamines have been examined. Racemic compounds were conveniently prepared by thermal Overman rearrangements of primary allylic alcohols with trisubstituted double bonds, but rearrangement of these substrates using the only commercially available compound known to catalyze enantioselective Overman rearrangements, the cobalt oxazoline palladacycle (R)‐COP‐Cl, failed. Instead, optically active secondary allylic alcohols with trisubstituted double bonds, obtained by Corey–Bakshi–Shibata reduction of the corresponding methyl ketones, were synthesized and converted into α,α‐disubstituted allylamines through a thermal Overman rearrangement or an allylic‐cyanate‐to‐isocyanate rearrangement. High chirality transfer (90–99 %) was obtained for both reaction sequences, but the yields were greatly improved when the allylic‐cyanate‐to‐isocyanate rearrangement was used.

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“…Ichikawa et al reported the synthesis of tert ‐butyl 3,7‐dimethylocta‐1,6‐dien‐3‐ylcarbamate ( 9 ) from the primary carbamate 7 , using triphenylphosphine, carbon tetrabromide, and triethylamine as dehydration system below room temperature (Scheme ) . Compound 8 is stable enough to be washed with a saturated aqueous NaHCO 3 solution or purified through a short column of silica gel.…”

Section: From Simple Allylic Alcohols To More Complex Substratesmentioning

confidence: 99%

The Allyl Cyanate/Isocyanate Rearrangement: An Efficient Tool for the Stereocontrolled Formation of Allylic C–N Bonds

et al. 2017

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[3,3]‐Sigmatropic rearrangements represent powerful methods in the toolbox of synthetic organic chemists for the stereoselective construction of carbon–carbon as well as carbon–heteroatom bonds. Thus, the allyl cyanate/isocyanate rearrangement, although still underused for the preparation of allylamine derivatives, offers clear advantages over other similar methods. It usually occurs at or below ambient temperature with no need to use any metal catalyst, in a stereospecific way, and with a complete transfer of chirality. Moreover, combined with the high reactivity of the resulting isocyanates towards nucleophiles, this rearrangement gives access to various classes of compounds with wide structural and functional diversity. This microreview provides an overview of synthetic applications of this rearrangement since its discovery, with particular emphasis on its utility for the synthesis of complex nitrogen‐containing molecules such as natural products.

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Allyl Cyanate‐To‐Isocyanate Rearrangement: Preparation of tert ‐Butyl 3,7‐Dimethylocta‐1,6‐dien‐3‐ylcarbamate

Cited by 3 publications

References 40 publications

A Total Synthesis of the Antifungal Deoxyaminocyclitol Nabscessin B from l-(+)-Tartaric Acid

A Total Synthesis of the Antifungal Deoxyaminocyclitol Nabscessin B from l-(+)-Tartaric Acid

Rearrangement Reactions Leading to Optically Active α,α‐Disubstituted Primary Allylamines

The Allyl Cyanate/Isocyanate Rearrangement: An Efficient Tool for the Stereocontrolled Formation of Allylic C–N Bonds

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