Substituted chromanes, analogs thereof, and methods of use and synthesis

A method of synthesizing a compound of formula,

• or a salt or hydrate thereof,
• the method comprising irradiating reagents comprising:
• (a) a compound having a formula selected from
• wherein:
• R1 and R2 are independently selected from hydrogen, alkyl, alkoxy, carboxy, and carboxyalkyl;
• R3 and R4 are independently selected from hydrogen, alkyl, alkoxy, carboxy, carboxyalkyl, aryl, carboxyalkylaryl (e.g., carboxybenzyl ester), and cyano;
• Optionally, wherein at least one of R1, R2, R3, and R4, is not hydrogen;
• R5, R6, R7, and R8 are independently selected from hydrogen, alkyl, alkoxy, halo and optionally R7 and R8 form an aryl group;
• X is selected from oxygen, nitrogen (NH), and carbon (CH2);
• and
• n is an integer selected from 0-1;
• (b) a photocatalyst selected from the group consisting of
• (c) a Lewis acid selected from the group consisting of Sc(OTf)3, M(OTf)2, La(OTf)3, and LiCl;
• and
• (d) a reducing agent, wherein the reducing agent is a Hantzsch ester of formula
• or
• N,N-diisopropylethylamine (DIPEA), triethylamine (NEt3), tributylamine 2 (NBu3), or 2-phenyl-dihydrobenzothaizoline (BT).