Stereoelectronic Aspects of the Prins Reaction Can undergo cy from Mac ian seminar. 1996 Oxocarbenium Ion formation 32C-023/18999:41PMR1 OH R OH R1 O R OH R1 OH R O R2 R2 O R O R2 R1 R1 O R2 O R H+ H+ Stereoelectronic Aspects of the Prins Reaction from MacMillan Seminar, 1996 + + R2CHO - H+ Cannot undergo cyclization Can undergo cyclization Me OLA O R Me OLA O R O LAO R O LAO R O R Me OLA O R O Oxocarbenium Ion Formation + + 10 - 14 kcal/mol + + (E)-Oxocarbenium ion (Z)-Oxocarbenium Ion + Prins pinacol 32C-02 3/18/99 9:41 PM