Synthese und Einkristallröntgenstrukturanalyse von Bromdi(isopropenyl)bismutan
摘要:
Tri(isopropenyl)bismuthane (1) reacts with bromine to form bromodi(isopropenyl)bismuthane (2) and dibromo(isopropenyl)bismuthane (3). The single crystal X-ray structure determination of 2 (monoclinic, P2(1)/c; a = 1058.6(3), b=1127.0(3), c=1561.3(4) pm, and beta = 109.26(2)degrees; Z=8 molecules; d(c)=2.803 g/cm(3); R=0.059) shows two crystallographically independent molecules which are connected by Bi-Br Bi bridges (Bi-Br 282.3(2) and 284.7(2); Br ... Bi 302.9(2) and 303.6(2) pm) forming helical chains directed along the b-axis of the unit cell. Every turn of the helix (360 degrees) consists of four molecules and corresponds to the length of the b-axis (1127.0(3) pm).
A highly enantioselective synthesis of chiral allylic alcohols by asymmetric addition of novel mixed reagents of trialkenylbismuthines/dialkylzincs to aldehydes
作者:Itaru Sato、Noriaki Asakura、Taizo Iwashita
DOI:10.1016/j.tetasy.2007.10.031
日期:2007.11
A novel mixture of reagents of trialkenylbismuthines/dialkylzincs was developed and applied toward the synthesis of chiral allylic alcohols. The chiral β-amino alcohols catalyzed addition of the mixed reagents of trialkenylbismuthines/dialkylzincs to aldehydes gave enantiomerically enriched allylic alcohols with up to 97% ee.