Asymmetric approaches to cyclopentenones in the Ni(0)-promoted cyclocarbonylation reaction of allyl halides and acetylenes

• Published in: Tetrahedron Vol. 52; no. 31; pp. 10525 - 10546
• Main Authors: Manuel Villar, Juan, Delgado, Antonio, Llebaria, Amadeu, Moretó, Josep M., Molins, Elies, Miravitlles, Carles
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 29.07.1996; Elsevier
• Subjects: Chemistry; Chemistry, Organic; Physical Sciences; Science & Technology; PARA-TOLYL; SULFOXIDES; SPIRO CYCLOPENTENONES; ALKYNES; CARBONYLATIVE CYCLOADDITION
• ISSN: 0040-4020; 1464-5416
• DOI: 10.1016/0040-4020(96)00573-X

Different approaches to the asymmetric synthesis of cyclopentenones by means of the Ni(CO) 4-promoted alkyne-allyl halide cyclization-carbonylation are reported. The use of acetylenic sulfoxides 1 has proved effective for the synthesis of acyclic, fused [5+8], and spiro [5+5], [5+7], and [5+8] cyclopentenones, whereas placement of the aryl sulfoxide on the allylic system failed to afford any cycloadduct. Homochiral fused [5+8], and spiro [5+7] and [5+8] cyclopentenones have been obtained by this methodology. Finally, a modest enantioselectivity was observed when different homochiral α-substituted carboxylates were used as ligands in our reaction system. Different approaches based on the use of sulfoxides as chiral auxiliaries or homochiral carboxylates as additives in the Ni(0)-promoted asymmetric synthesis of cyclopentenones are reported and compared.