In chemistry, the descriptor geminal (from Latin gemini 'twins' [1]) refers to the relationship between two atoms or functional groups that are attached to the same atom. A geminal diol, for example, is a diol (a molecule that has two alcohol functional groups) attached to the same carbon atom, as in methanediol.

1993年3月5日 · In a recent paper, M.E. Jung4 has provided clear evidence, that the gem.-dimethyl effect is essentially enthalpic in nature and most likely due to the presence of reactive rotamers. In this paper we investigate the structural features of open chain compounds, cyclopentanes and cyclohexanes, all bearing geminal dimethyl groups.

2023年6月2日 · Xiong, W. et al. Geminal dimethyl substitution enables controlled polymerization of penicillamine-derived β-thiolactones and reversed depolymerization. Chem 6, 1831–1843 (2020).

2-chloroethanol with a gem-dimethyl group produces an increase of ˘200-fold in the rate of ring closure. A similar rate enhancement is observed when the gem-dimethyl group is placed next to the attacking nucleophile. It is noteworthy that the simultaneous replacement of all four hydrogens of 2-chloroethanol

The Thorpe–Ingold effect, gem-dimethyl effect, or angle compression is an effect observed in chemistry where increasing steric hindrance favours ring closure and intramolecular reactions. The effect was first reported by Beesley, Thorpe, and Ingold in 1915 as part of a study of cyclization reactions. [1] .

By introducing a gem-dimethyl substitution, we succeeded in regulating both the forward polymerization of β-thiolactones and the backward depolymerization of polythioesters in a highly controlled fashion and with low energy input. Moreover, our strategy allows facile access to semicrystalline plastics with tailorable mechanical and thermal ...

2024年4月9日 · Their chemical recycling study revealed that P(γ-DMCL) could be efficiently and selectively recycled back to γ-DMCL. This study explored the application of geminal dimethyl substitution strategy in chemically recyclable polyamides and allowed access to diversified and different polyamide products.

2008年2月16日 · Geminal Dimethyl Substitution Enables Controlled Polymerization of Penicillamine-Derived β-Thiolactones and Reversed Depolymerization. Chem 2020, 6 (7) , 1831-1843. https://doi.org/10.1016/j.chempr.2020.06.003

2020年12月1日 · Demethylation of angular methyl groups via geminal-diol or aldehyde intermediates by a single oxygenase. The geminal-diol or aldehyde intermediates are highlighted by labeling the geminal-diol and aldehyde with red color.

2017年8月29日 · The gem -dimethyl moiety is a structural feature frequently found in many natural products of clinical interest, including, but not limited to, taxanes, epothilones, statins, retinoids, di-/triterpenes, noviose deoxysugar, and antibiotics derived from β-lactams, macrolides, and aminocoumarins.