Enantioselective Synthesis of Medium-Ring Heterocycles, Tertiary Ethers, and Tertiary Alcohols by Mo−Catalyzed Ring-Closing Metathesis

Abstract

The Mo-catalyzed asymmetric ring-closing metathesis (ARCM) of various achiral trienes leads to the formation of medium-ring unsaturated heterocycles in high yield and with excellent enantioselectivity. Reactions may be carried out on gram scale and in the absence of solvent. The unsaturated siloxanes obtained enantioselectively can be readily functionalized to obtain synthetically useful and difficult-to-access tertiary alcohols.

Studies on the Origin of 1,5‐anti Induction in Boron‐Mediated Aldol Reactions

“…a Schock/Hovedya molybdenum catalyst, [18] but this gave only unmodified starting material. [19] With the required substrates in hand, we turned our attention towards the aldol reaction of 2 and the comparison of an aromatic vs. nonaromatic participating group.…”

Enantioselective synthesis of cyclic allylboronates by Mo-catalyzed asymmetric ring-closing metathesis (ARCM). A one-pot protocol for net catalytic enantioselective cross metathesis

“…15,16 Such C -C bond forming reactions are less feasible with the corresponding cyclic siloxanes that can also be obtained through Mo-catalyzed ARCM reactions. 17 Although Mocatalyzed ARCM of allylsiloxanes allows access to products shown in Scheme 2 and Table 1 through oxidations of the C -Si bonds, the present method offers a more attractive option. This preference is for two reasons: (i) C -Si oxidation is generally less efficient than those of C -B bonds and with allylsilane compounds such processes can occur with low regioselectivity.…”

Monolithic Disk‐Supported Metathesis Catalysts for Use in Combinatorial Chemistry

“…RuCl 2 (PCy 3 ) 2 (CHPh) was purchased from Fluka. endo-Norborn-2-ene-5-carboxylic chloride, [67] (NBE-CH 2 O) 3 SiCH 3 , [42] (R)-5,5'-bis-(norborn-5-ene-2-ylmethyleneoxymethyl)-3,3'-ditert-butyl-6,6'-dimethylbiphen-2,2'-diol, [29] 2,6-dimethyl-4-(allyldimethylsilyloxy)-hepta-1,6-diene, [58] 2,4-dimethyl-3-(dimethylvinylsilyloxy)-penta-1,4-diene, [68 -70] N-(isobut-1-en-3-yl)-N-(4-phenylbut-1-en-4-yl)aniline, [55] N-(allyl)-N-(2-methyl-4-phenylbut-1-en-4-yl)aniline, [55] 3-allyloxy-3-phenylisobut-1-ene, [65] 3-allyloxy-2,4-dimethylpenta-1,4-diene, [29,68 -70] RuCl 2 (PCy 3 )(NHC)(CHPh) [NHC ¼ 1-mesityl-3-(6-hydroxyhexyl)imidazl-2-inylidene], [22] and Mo[N-2,6-(i-Pr) 2 -C 6 H 3 ]-(CHCMe 2 Ph)(OSO 2 CF 3 ) 2 .DME [71] were prepared according to literature procedures and checked for purity by means of NMR.…”