SN1 and the Carbocation: When the back is blocked

English translation in progress. The Chinese version is the authoritative source. 中文版正文已发布，英文翻译进行中。

In the meantime:

• Read the Chinese version at the Chinese episode page.
• Watch the YouTube episode (English subtitles included).
• Get notified when the English essay is published — RSS feed is at /rss.xml.

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Abstract

When 3° substrates close the back to SN2, the carbon lets go first — planar sp² carbocation, nucleophile attacks either face, the result is statistical partial racemization.

The full English essay will mirror the 10-section structure of the Chinese original: framing, history (Walden 1896 for Episode 01), bimolecular kinetics, orbital geometry of backside attack, trigonal bipyramidal transition state, umbrella inversion, stereochemical consequences with worked examples, biology (SAM methylation, MGMT DNA repair, thalidomide), the NGP reading of Walden’s cycle, and a closing comparison setting up the next episode.

Estimated publication: within two weeks of the Chinese version.