Collect. Czech. Chem. Commun. 1999, 64, 1049-1056
https://doi.org/10.1135/cccc19991049

Syntheses with Organoboranes. X. Monohydroboration of Conjugated Enynes with Catecholborane Catalyzed by Nickel(II) Chloride Complexes with Diphosphines

Marek Zaidlewicz* and Jerzy Meller

Faculty of Chemistry, Nicolaus Copernicus University, 87-100 Toruń, Poland

This article is part of serial Syntheses with Organoboranes.

Abstract

The monohydroboration of representative conjugated enynes - but-1-en-3-yne (1), 2-methylbut-1-en-3-yne (2), pent-3-en-1-yne (3), hex-1-en-3-yne (4), 2-methyl-4-phenylbut-1-en-3-yne (5), 4-methyl-1-phenylpent-3-en-1-yne (6) and 1-ethynylcyclohex-1-ene (7), with catecholborane in the presence of the nickel(II) chloride complex with 1,2-bis(diphenylphosphino)ethane gave the corresponding 1,3-dien-1-yl organoboranes in 54-87% yield. High regioselectivity of the addition leading to the boron atom at the 4-position of the 1-en-3-yne system was observed for 1, 2, 3, 6 and 7.

Keywords: Catalytic hydroboration; 1,3-Dien-1-yl organoboranes; 1-En-3-ynes; Catecholborane; Boronates; Alkynes; Nickel.