Stereo- and regio-selective synthesis of polyfunctionalized cyclopropanes

Stereoselective Synthesis Using Diastereotopic Groups

“…Depending on the camphor auxiliary, moderate to good diastereoselectivity in favour of 89 is realized. 64,65 The mode of diastereoselection in this case is not clear. It could either occur in a diastereoselective irreversible lithiation of one of the thiomethyl groups, or in the carbenoid C-H-insertion step after reversible lithiation.…”

Recent Advances in Synthesis of Cyclopropanes

“…The 2-carbamoyl derivative, 8, undergoes successive cyclization and (8) (9) chelation-controlled lithiation to give 9, when treated with excess butyllithium, which provides bicyclic γ -butyrolactones, 10, upon exposure to aldehydes (equation 10) 21 . Sequential treatment of the 2-formyl derivative with alkyllithium and DMF stereoselectively (10) furnishes bicyclic lactols, 11, in an analogous manner (equation 11) 22 . An asymmetric cyclization is realized with the carbamoyl derivatives modified with chiral amines and (11) trans-2-(phenylthio)cyclopropanecarboxamides are obtained in diastereomeric excesses (de) up to 83% (equation 12) 23 .…”