A Scalable Protocol for the Regioselective Alkylation of 2-Methylcyclohexane-1,3-dione with Unactivated sp3 Electrophiles.

A method for the C-selective alkylation of 2-methylcyclohexane-1,3-dione with unactivated sp3 electrophiles is accomplished via alkylation and subsequent deprotection of the derived ketodimethyl hydrazones. The present method provides a high-yielding entry to dialkyl cycloalkanones that cannot be accessed via direct alkylation of 2-methylcyclohexane-1,3-dione. The title reaction may be useful in the scalable preparation of terpene and steroidal building blocks in the arena of natural product synthesis.

Width ratios in the anterior maxillary region in a Hungarian population: addition to the golden proportion debate.

STATEMENT OF PROBLEM: In the last 2 decades, several studies have questioned the application of the rule of golden proportion in dentistry. PURPOSE: The purpose of this study was to test the rule of golden proportion for the maxillary anterior region in a population of young, healthy people with excellent oral hygiene at the Faculty of Dentistry of the University of Szeged. MATERIAL AND METHODS: One hundred and nine participants (36 male, 73 female) were examined, 41 of whom had previously worn orthodontic appliances. A Canon 450D camera, Canon 100 mm Macro lens, and a Sigma 140 DG ring flash were used for digital documentation. The accreditation photography protocol of the American Academy of Cosmetic Dentistry was applied to standardize the images. The width of the teeth from the frontal view was measured digitally. Tooth dimension data were collected and the Mann-Whitney U test was performed (α=.05). RESULTS: The relative width of the central incisors, lateral incisors, and canines was 1.6:1:0.85 on both sides. The ratios were not influenced by either sex or previous orthodontic treatment. CONCLUSIONS: The results demonstrated that, because of the difference in canines in this population, the golden proportion in its original form was not valid for the maxillary anterior region. Orthodontic treatment does not change the dentition toward the golden proportion. The results suggest that the rule of golden proportion should not be used for treatment planning without observing individual modifying factors.