(S)-(+)-2,2-Dimethyl-1,3-dioxolane-4-methanol
[CAS 22323-82-6]

Identification

• Classification: Organic raw materials >> Ketone compound
• Name: (S)-(+)-2,2-Dimethyl-1,3-dioxolane-4-methanol
• Synonyms: (+)-2,3-O-Isopropylidene-sn-glycerol; (S)-(+)-Solketal
• Molecular Formula: C₆H₁₂O₃
• Molecular Weight: 132.16
• CAS Registry Number: 22323-82-6
• EC Number: 244-910-8
• SMILES: CC1(OC[C@@H](O1)CO)C

Properties

• Density: 1.0±0.1 g/cm³ Calc.^*, 1.066 g/mL (Expl.)
• Boiling point: 188.5 °C 760 mmHg (Calc.)^*, 215.9 - 217.3 °C (Expl.)
• Flash point: 80.0 °C (Calc.)^*, 79 °C (Expl.)
• Solubility: water: miscible (Expl.)
• Index of refraction: 1.424 (Calc.)^*, 1.434 (Expl.)
• Alpha: 11 ° (c=5, CH3OH) (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H227-H315-H319-H335
• Safety Statements: P210-P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P370+P378-P403-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Flammable liquids	Flam. Liq.	4	H227
Eye irritation	Eye Irrit.	2A	H319

chemBlink Chemical Story

(S)-(+)-2,2-Dimethyl-1,3-dioxolane-4-methanol, commonly known as (S)-Solketal or (S)-2,3-O-isopropylideneglycerol, is a chiral glycerol derivative widely used as a synthetic intermediate. Although the molecule itself has no major commercial application as a finished product, it has become one of the most important chiral building blocks in modern organic synthesis. Its significance lies not in its intrinsic properties, but in the elegant way it combines stereochemical control with selective protection of functional groups, enabling the efficient preparation of numerous biologically active compounds.

The compound originates from glycerol, one of the simplest naturally occurring polyols. Glycerol is inexpensive, readily available from both natural fats and biodiesel production, and possesses an inherent prochiral framework. During the development of stereoselective organic synthesis in the latter half of the twentieth century, chemists recognized that glycerol could serve as an attractive renewable source of chirality. Selective preparation of enantiomerically pure glycerol derivatives therefore became an important objective in synthetic chemistry.

One of the most successful solutions was the formation of the acetonide protecting group. Reaction of glycerol derivatives with acetone converts two neighboring hydroxyl groups into a five-membered 1,3-dioxolane ring while leaving the remaining hydroxymethyl group available for further transformation. This apparently simple modification accomplishes two essential tasks simultaneously: it protects two reactive hydroxyl groups from undesired side reactions and preserves a single functional handle that can be selectively manipulated. The resulting molecule is both chemically stable and highly versatile.

As asymmetric synthesis matured during the 1970s and 1980s, (S)-Solketal emerged as a standard chiral synthon. The defined stereochemistry inherited from glycerol allows subsequent reactions to proceed with predictable stereochemical outcomes, avoiding many of the difficulties associated with racemic mixtures. Consequently, the compound has been employed in the synthesis of carbohydrates, nucleoside analogues, amino alcohols, phospholipids, natural products, pharmaceuticals, and numerous chiral auxiliaries and ligands. In many synthetic routes, the molecule serves as a common starting point from which increasingly complex molecular architectures can be constructed.

The widespread adoption of (S)-Solketal also reflects the growing importance of protecting-group chemistry. Before selective catalytic methods became widely available, temporary protection of functional groups was often indispensable for controlling reaction sequences. The acetonide group became one of the most frequently used protecting groups for vicinal diols because it is readily introduced, remains stable under many reaction conditions, and can later be removed under relatively mild acidic conditions. These characteristics have made glycerol acetonides enduring tools in synthetic methodology.

Beyond laboratory research, (S)-Solketal has found extensive use in industrial process development. Pharmaceutical manufacturers employ it as a chiral intermediate in the preparation of active pharmaceutical ingredients, while fine chemical producers use it as a versatile precursor for specialty chemicals. Interest in renewable feedstocks has further enhanced its value, since glycerol derived from biomass provides a sustainable starting material for producing optically active intermediates.

The scientific importance of (S)-(+)-2,2-Dimethyl-1,3-dioxolane-4-methanol therefore extends far beyond its molecular structure. It represents the convergence of three influential concepts in modern organic chemistry: the use of renewable natural feedstocks, the strategic application of protecting-group chemistry, and the efficient transfer of chirality through carefully designed synthetic building blocks. Although rarely the final target of a synthesis, it has quietly enabled the preparation of countless complex molecules and remains one of the classic chiral building blocks of contemporary organic chemistry.

**References**

1. Greene, T. W. and Wuts, P. G. M. *Protective Groups in Organic Synthesis*, 5th ed., John Wiley & Sons, 2014.

2. Hanessian, S. *Preparative Carbohydrate Chemistry*, Marcel Dekker, 1997.

3. Sheldon, R. A. *Green and Sustainable Manufacture of Chemicals from Biomass: State of the Art*, Green Chemistry, 2014, 16, 950–963.