The acetylide attacks the less substituted terminal epoxide carbon by SN2 ring opening. The C–O bond at that carbon breaks, leaving the oxygen attached to the original substituted stereocentre. Protonation gives . Dissolving-metal reduction then gives the E alkene and also cleaves the benzyl ether.
Thus H is with an E double bond, and its original epoxide-derived stereocentre is retained geometrically. No new tetrahedral stereocentre is formed: the attacked epoxide carbon becomes CH. The new stereochemical information is the E alkene geometry. Calling its secondary hydroxyl carbon “newly generated” would confuse changing its functional environment with creating a new stereocentre.

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