Synthesis of Some Bioactive Acetylenic Alcohols, Components of the Marine Sponge Cribrochalina vasculum

Article abstract of DOI:10.1021/jo00074a022

Grignard coupling of isopropylmagnesium bromide with 4-(tetrahydropyranyloxy)bromobutane (2) and subsequent bromination gave 4.Alkylation of 1-(tetrahydropyranyloxy)undec-10-yne (5) with 4 and 1-bromohexane, acidic hydrolysis, and bromination furnished 7 and 9, respectively.Likewise, coupling of isobutylmagnesium bromide with 12-(tetrahydropyranyloxy)bromododecane (12) followed by bromination afforded 14.Alkylation of 1-(tetrahydropyranyloxy)-2-propyne (15) with 7, 9, and 14 and oxidation of the respective products afforded the alkynals 16a-c.These on reaction with lithium acetylide and subsequent chemoselective trans reduction of the internal alkynes led to the target compounds I-III.