[azmanam]

QUESTION:  The acid catalyzed cyclization of the trans epoxide starting material yields a single kinetic product.  Predict the kinetic product of this reaction and the relative stereochemistry of the product.  Provide a visual orbital explanation that accounts for the selectivity of this process.

[azmanam]

*Ignore me, I am impatient*

[sjb]

Well, I think the answer is probably related to Baldwin's guidelines, but then again I thought these did not really apply to acidic solutions. If I'm on the right track, I think the tetrahydrofuran ring is the preferred product. Not 100% sure of stereochem, I'll keep scratching my head.

[azmanam]

on the right track.  It's not formally Baldwin, but - er - Baldwin-esque.

[blind]

A bit late to the party, but could it be because of better overlap of the lone pairs on the oxygen with the antibonding orbitals of C-O bond in the formation of THF?

[azmanam]

That is in fact why.  Well done.  Orbital overlap is what drives most of Baldwin's rules, if I'm not mistaken.

Sorry for not posting new questions.  I got caught up in back-to-school and applying-for-job stuff.  I'll get a new one up mondayish