Organometallic reagents and protocols for synthesis

Abstract The addition of vinyl, aryl and alkynyl Grignard reagents to propargyl alcohols for the direct synthesis of dihydroxydienes ( 7 ), furans ( 9 ), butenolides ( 10 ) and enediyne alcohols ( 11 ) from a one-pot reaction involving a putative magnesium chelate intermediate ( 3 ) is described. Treatment of 5-bromo-1,3-pentadiene with indium metal in the presence of carbonyl compounds resulted in γ-pentadienylation to generate 1,4-dienes ( 30 ). Dehydration afforded cross-conjugated trienes ( 31 ) for tandem Diels–Alder reactions, while the alcohol product ( 34 ) from an unsaturated aldehyde after oxy-Cope rearrangement afforded the 1,4-diene product ( 35 ) and ultimately hydrindane ( 36 ).