Stan S. Hall

Efficient Syntheses of β-Sesquiphellandrene and Zingiberenol Employing a Tandem Arylation-Multistep Reduction-Hydrolysis Sequence1

Abstract The title sesquiterpenes are synthesized in one step from the common intermediate 4-(6-methyl-5-hepten-2-yl)-2-cyclohexen-1-one, which is prepared using a one-pot tandem arylation-multistep reduction-hydrolysis sequence.

Alkylation-Reduction of Carbonyl Systems. V. The Selective Synthesis of o-Tolylphenylmethanol and o-Tolylphenylmethane by Phenylation-Reduction of Benzocyclobutenone

Abstract For some time this laboratory has been developing the concept of tandem alkylation-reduction as a convenient method of preparing aromatic hydrocarbons by the lithium-ammonia reduction of benzyl alkoxides generated in situ by alkylation.1 In these as well as related metal-ammonia reduction studies we have also demonstrated the mechanistic advantages and selective synthetic utility of comparing sodium benzoate2 vis-a-vis ammonium chloride as quenching agents for the lithium-ammonia reduction step.1a,b,3 Herein we wish to describe the application of these procedures to the strained aromatic carbonyl system benzocyclobutenone (1)4 that resulted in the selective synthesis of either o-tolylphenylmethanol (4) or o-tolylphenylmethane (5) depending on the quenching agent.

Alkylation–reduction of aromatic ketones and aldehydes. A convenient synthesis of aromatic hydrocarbons

Aromatic hydrocarbons are prepared from aromatic ketones and aldehydes by alkylation with an organolithium reagent followed by lithium–ammonia reduction in the same reaction vessel without isolation of intermediates.

Phenyl- and mesitylglyoxylic acids: catemeric hydrogen bonding in two α-keto acids

alpha-Oxobenzeneacetic (phenylglyoxylic) acid, C(8)H(6)O(3), adopts a transoid dicarbonyl conformation in the solid state, with the carboxyl group rotated 44.4 (1) degrees from the nearly planar benzoyl moiety. The heterochiral acid-to-ketone catemers [O.O = 2. 686 (3) and H.O = 1.78 (4) A] have a second, longer, intermolecular O-H.O contact to a carboxyl sp(3) O atom [O.O = 3.274 (2) and H.O = 2.72 (4) A], with each flat ribbon-like chain lying in the bc plane and extending in the c direction. In alpha-oxo-2,4, 6-trimethylbenzeneacetic (mesitylglyoxylic) acid, C(11)H(12)O(3), the ketone is rotated 49.1 (7) degrees from planarity with the aryl ring and the carboxyl group is rotated a further 31.2 (7) degrees from the ketone plane. The solid consists of chiral conformers of a single handedness, aggregating in hydrogen-bonding chains whose units are related by a 3(1) screw axis, producing hydrogen-bonding helices that extend in the c direction. The hydrogen bonding is of the acid-to-acid type [O.O = 2.709 (6) and H.O = 1.87 (5) A] and does not formally involve the ketone; however, the ketone O atom in the acceptor molecule has a close polar contact with the same donor carboxyl group [O.O = 3.005 (6) and H.O = 2.50 (5) A]. This secondary hydrogen bond is probably a major factor in stabilizing the observed cisoid dicarbonyl conformation. Several intermolecular C-H.O close contacts were found for the latter compound.