Se. Denmark et S. Hosoi, STEREOCHEMICAL STUDIES ON THE ADDITION OF ALLYLSTANNANES TO ALDEHYDES- THE S-E' COMPONENT, Journal of organic chemistry, 59(18), 1994, pp. 5133-5135
The disposition of the tin electrofuge in the cyclization of (l)-1 and
(u)-1 has been established to be anti S-E' under Lewis and Bronsted a
cid promotion and syn S-E' under thermal conditions.