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The Chemical Educator

ISSN: 1430-4171 (electronic version)

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Abstract Volume 16 (2011) pp 208-210

A Simple Two-“Finger” Method for Determination of R or S Configuration at a Stereogenic Center

Erach R. Talaty

Department of Chemistry, Wichita State University, Wichita, KS 67260-0051, U.S.A.
Received September 1, 2010. Accepted July 5, 2011.

Published: 20 August 2011

Abstract. A method for determination of absolute configuration at a stereogenic center is presented, which depends on conversion of any perspective drawing into a Fischer projection. In this novel method, one uses only the index finger and thumb of a hand and the ability to rotate it at the wrist. Thus, students are not dependent on models, which are obviously prohibited in examinations, but can freely use their hands. This procedure avoids the usual pitfalls involved in exchanging groups so that the group having priority No. 4 is always placed below the plane of the paper, which is generally recommended by many authors of textbooks, and often confuses the students. Moreover, it is applicable for stereogenic centers in rings as well as multiple chiral centers.

Key Words: In the Classroom; organic chemistry

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