Elimination of beta-thioalkoxy alcohols under Mitsunobu conditions. A new synthesis of conjugated enynes from propargylic dithioacetals.
Treatment of propargylic dithiolanes 1 with (n)BuLi followed by a carbonyl electrophile yields the corresponding homopropargylic alcohol 3. Upon treatment with 2 equiv of PPh3 and DIAD, elimination of SR and OH moieties from 3 affords the corresponding olefins 4 in moderate to good yield. The reaction can be considered an alternative of McMurry coupling of two different carbonyl equivalents.
Chen
Chih-Wei
CW
Department of Chemistry, National Taiwan University, Taipei, Taiwan 106, Republic of China.
Luh
Tien-Yau
TY