Transition-Metal-Free Reductive Coupling of 1,3-Butadienes with Aldehydes Catalyzed by Dibutyliodotin Hydride

Abstract

In this study, the BuSnIH-catalyzed direct coupling of 1,3-dienes with aldehydes was developed. This reaction could be suitable for coupling without the use of transition-metal catalysts. Many types of aldehydes were applied to this reaction. The addition of MeOH promoted the catalytic cycle.

Catalytic Annulation of Epoxides with Heterocumulenes by the Indium-Tin System

“…All epoxides, isocyanates, carbodiimide and InCl 3 were also purchased and used as obtained. Bu 2 SnI 2 was prepared according to the previous report [ 74 ].…”

Reductive coupling of allenoates with aldehydes catalyzed by halogenotin hydride

“…The reaction conditions were optimized using ethyl 2-methylbuta-2,3-dienoate ( 1a ), benzaldehyde ( 2a ), and Bu 2 SnCl(OMe) as a pre-catalyst, which is converted to Bu 2 SnClH in situ by Ph 2 SiH 2 . According to our previous work, 24 the addition of MeOH promotes the reaction via the protonation of a reaction intermediate. First, we screened reaction solvents at 60 °C and found that cyclopentyl methyl ether (CPME) worked well to give the product 3aa (entries 1–5).…”

Direct use of 1,3-dienes for the allylation of ketones via catalytic hydroindation

“…Our group has explored the hydrostannylation 11 or indation 12 of unsaturated bonds in the preparation of reactive organostannanes or indiums that could be applied to further transformations, although stoichiometric amounts of Sn or In sources must be added to the reaction systems. Recently, a transition metal-free reductive coupling of 1,3-dienes, 13 or their derivatives such as vinyl cyclopropanes, 14 with aldehydes catalyzed by Bu 2 SnXH has been developed, but the method would not allow the use of ketones due to the low reactivity of the reaction intermediate, allylic stannanes (Scheme 1c). On the other hand, our group has already developed a process for the hydroindation of 1,3-dienes with a stoichiometric amount of InX 2 H to give allylic indiums followed by the allylation of ketones.…”

“…Based on our previous reports, InCl 2 OMe generated from InCl 3 /NaOMe and a silane were chosen as indium and hydride sources, respectively. 13 The desired product 3aa was obtained in a 92% yield as a mixture of Scheme 1 Synthesis of homoallylic alcohols from allylation reagents with ketones.…”

“…b-Keto ester 2l was a good partner even though a similar chelation involving two C]O groups could have happened (entry 12). Both acyclic and cyclic aliphatic ketones were allylated (entries [13][14]. Other aromatic rings such as naphthalenes were introduced into the products 3ao and 3ap (entries 15 and 16).…”