Oallylated

Oallylated refers to a chemical compound in which a hydroxyl group (from an alcohol or phenol) has been converted into an allyl ether by O-allylation. In this transformation, the hydrogen of the hydroxyl is replaced by an allyl group (−CH2−CH=CH2), yielding RO−CH2−CH=CH2. The term is commonly used in organic synthesis and in discussions of protecting groups.

The standard method for O-allylation is the Williamson ether synthesis, where an alkoxide or phenoxide is formed first by deprotonation with a base, followed by reaction with an allyl electrophile such as allyl halide (e.g., allyl bromide or allyl chloride) or an allyl sulfonate/tosylate. Bases often employed include sodium hydride, potassium carbonate, or cesium carbonate, with solvents such as acetone, DMF, or DMSO. Alternative approaches use preactivated allyl donors like allyl carbonates or allyl boron reagents.

O-allylation is widely used as a protecting strategy for alcohols and phenols because allyl ethers generally withstand many reaction conditions and can be removed under mild conditions. Deprotection commonly exploits palladium-catalyzed deallylation (Tsuji–Troost type) or catalytic hydrogenolysis, enabling selective unveiling of the hydroxyl group in multi-step syntheses.

In practice, the choice of allylating agent and conditions depends on substrate sensitivity and the desired timing of deprotection. O-allylated compounds appear across pharmaceuticals, natural products, and complex organic syntheses, often serving as versatile intermediates or protecting groups.

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