Sir: In connection with natural product synthesis, we have been concerned with the problem of converting a,p-unsatu- rated compounds into cyclopropanes (eq 1) and recently de- ... R r 0 veloped a method to accomplish this; however, the open chain hydrocarbon was also formed (eq 2).l We now report another 1. C6HjSH 2. LiAlH, 3. CH,SO,Cl/Pyr 5 Li/NH, R' R' 0 2. LiAlH, R ... 3. CH,SO,Cl/Pyr 5. Li/NH, I II R' 0 R' ... + R* (2) R approach which cleanly gives the ...