Highly regioselective synthesis of gem-difluoroallenes through magnesium organocuprate S(N)2 ' substitution

作者：Mae M^*; Hong JA; Xu B; Hammond GB

来源：Organic Letters, 2006, 8(3): 479-482.

DOI：10.1021/ol052816g

[GRAPHICS]
The reaction of gem-difluoropropargyl electrophiles with Grignard reagents is complicated by the inherent difficulty of executing nucleophilic substitutions on a CF2 group, and the facile formation of carbenoid intermediates arising from alpha-elimination of fluoride. In the presence of an excess amount of a copper salt, a Grignard reagent reacts with gem-difluoropropargyl bromide via an SINT mechanism to produce gem-difluoroallene in high yield. If desired, the resulting difluoroallene can undergo a second nucleophilic attack on the CF2 terminus to yield a trisubstituted monofluoroallene through an addition-elimination mechanism.

• 出版日期2006-2-2